The prospect of a transnational feminist coalition is one of the most challenging questions that feminism faces today. The author analyzes Beauvoir’s involvement with the Algerian decolonization movement and her own self-critique as instructive tools for forming better ways for feminists to engage transnationally. Beauvoir’s existentialist ethics, political writings, and activism continue to offer models for developing an anticolonial and anti-imperialist transnational feminist ethics and are an underexplored resource in transnational feminist scholarship.
We study emulation-based stabilisation of nonlinear networked control systems communicating over multiple wireless channels subject to packet loss. Specifically, we establish sufficient conditions on the rate of transmission that guarantee ℒp stability-in-expectation of the overall closed-loop system. These conditions depend on the cumulative dropout probability of the network nodes for static protocols. We use the obtained stability results to study power control, where we show there are interesting trade-offs between the transmission rate, transmit power, and stability. Lastly, numerical examples are presented to illustrate our results.
We propose a unifying emulation-based design framework for the event-triggered control of nonlinear systems that is based on a hybrid small-gain perspective. We show that various existing event-triggered controllers fit the unifying perspective. Moreover, we demonstrate that the flexibility offered by our approach can be used for the development of novel event-triggered schemes and for a systematic modification and improvement of existing schemes. Finally, we illustrate via a simulation example that these novel and/or modified event-triggered controllers can lead to a reduction in the required number of transmissions, while still guaranteeing the same stability properties.
Minimum attention control proposed by Brockett is an important formulation for resource-aware control, while his problem formulation and the underlying optimization problem that he proposed is in general very hard. In this paper, we propose a computationally tractable design method of minimum attention control based on promoting sparsity of the derivative of control. The optimal control problem is formulated as L0 norm minimization of the time derivative of control under the constraint that the derivative is bounded by a fixed value. This is a non-convex problem, and we propose L1 relaxation for linear systems to obtain optimal control by efficient numerical computation. We then show equivalence theorems between the L0 and L1 optimal controls. Also, we present an example of feedback control for the first-order integrator, that illustrates the proposed methodology.
This paper studies the behaviour of observers for the slow states of a general singularly perturbed system – that is a singularly perturbed system which has boundary-layer solutions that do not necessarily converge to a slow manifold. The solutions of the boundary-layer system are allowed to exhibit persistent (e.g. oscillatory) steady-state behaviour which are averaged to obtain the dynamics of the approximate slow system. It is shown that if an observer has certain properties such as asymptotic stability of its error dynamics on average, then it is practically asymptotically stable for the original singularly perturbed system.
Carbonation of concrete is generally assumed to lead to reinforcing steel corrosion. This mindset has long dictated the research priorities surrounding the developments towards new, low-emission binders. Here, by reviewing documented practical experience and scientific literature, we show that this widely held view is too simplistic. In fact, there are many cases from engineering practice where carbonation of the cementitious matrix surrounding the steel did not lead to noticeable corrosion or to corrosion-related damage at the level of a structure. The influencing factors that can, however, lead to considerable corrosion damage are identified as the moisture state, the microstructure of the carbonated concrete, various species that may be present – even in minor amounts – in the concrete pore solution, and the cover depth. The circumstance that a reduced pH alone is not sufficient to lead to significant steel corrosion in concrete seriously challenges the established approach of assessing the durability performance based on carbonation testing and modeling. At the same time, this circumstance offers great opportunities for reducing the environmental impact of concrete structures with low-emission binders. To realize these opportunities, the focus in research and engineering should shift from studying carbonation to studying corrosion of steel in carbonated concrete.
In this paper we address the problem of optimal co-design of control and quantization policies for a physically-interconnected system, where each subsystem has a local quantizer. The controllers are assumed to communicate with delay and cooperate in minimizing global quadratic cost. We show that for quantizers that act on the estimation error of the estimator conditioned on common information between controllers, separation holds. In other words, both quantizers can be optimally designed by minimizing a distortion function that is control-independent. Finally, for general class of quantizers we provide structural properties of the optimal control policy.
Korisnici Nacionalne i univerzitetske biblioteke Bosne i Hercegovine u svrhu različitih istraživanja često traže građu koja sadrži podatke o nacionalnoj i lokalnoj historiji, politici, kulturi. Nacionalna i univerzitetska biblioteka Bosne i Hercegovine svoje fondove, pored obaveznog primjerka, popunjava razmjenom i poklonima. Jedan takav poklon jeste i zaostavština historičara Hamdije Kapidžića. Biblioteka je ovaj poklon zaprimila 2008. godine. Dio poklona, koji čine nekoliko predmeta, korespondencija, pisma, razglednice, stare knjige, karte, nalazi se na Odjeljenju Specijalnih zbirki. Građa već duže vrijeme stoji neobrađena pa smo odlučili kroz ovaj kratki pregled i popis javnosti predočiti arhivu ovog znamenitog bosanskohercegovačkog kulturnog i naučnog radnika. Nadamo se da će ovaj kratak osvrt na zaostavštinu historičara Hamdije Kapidžića donijeti nove poglede na njegov život i znanstveni rad i poslužiti kao izvor za nova istraživanja.
Deep eutectic solvents (DESs), as an alternative to ionic liquids, have greener credentials than ionic liquids and have attracted increasing attention in many applications. Choline chloride-based DESs in combination with different hydrogen bond donors (organic acid, sugars and urea), showed a high extraction efficiency. The aim of this study was to examine the possible effects of choline chloride-based eutectic solvents on the antioxidant and antimicrobial activity of lemon and mandarin orange seed extracts. Lactic acid, glucose, urea and water were used to prepare choline chloride-based Natural Deep Eutectic Solvents (NADESs). Ferric-Reducing Antioxidant Power (FRAP) Assay and 2,2-diphenyl-1-picryl-hydrazyl (DPPH) method were used to determine Original Research Article Kolarević et al.; IRJPAC, 21(23): 120-128, 2020; Article no.IRJPAC.63470 121 antioxidant activity. Antibacterial activity was investigated by diffusion method on reference bacterial strains E. coli, E. faecalis, S. aureus, B. subtilis and L. monocytogenes. The analysis revealed a significant reduction potential of the eutectic solvent based on lactic acid as well as significant antioxidant activity of lemon and mandarin seed extracts. In general, mandarin extracts showed better antioxidant capacity. In vitro antibacterial activity assays showed a complete absence of bacterial growth inhibition of the extracts. However, eutectic solvents with lactic acid have shown a significant antimicrobial effect.
In adults 65 years or older, falls or other neuromotor dysfunctions are often framed as walking-related declines in motor skill; the frequent occurrence of such decline in walking-related motor skill motivates the need for an improved understanding of the motor skill of walking. Simple gait measurements, such as speed, do not provide adequate information about the quality of the body motion’s translation during walking. Gait measures from accelerometers can enrich measurements of walking and motor performance. This review article will categorize the aspects of the motor skill of walking and review how trunk-acceleration gait measures during walking can be mapped to motor skill aspects, satisfying a clinical need to understand how well accelerometer measures assess gait. We will clarify how to leverage more complicated acceleration measures to make accurate motor skill decline predictions, thus furthering fall research in older adults.
In this work we adapt and evaluate different solutions for automatic speech recognition (ASR) to be used as an HMI for the assistant robot. Two on-device solutions: Kaldi (DNN-HMM) and Mozilla's DeepSpeech (end-to-end), and three internet service APIs: IBM Watson, Microsoft Azure and Google Speech to Text are evaluated. The systems are adapted to the domain of robot commands and evaluated on a set of expected inputs. As the goal is to retain the ability to recognise general language, the systems are also evaluated on out of domain data.
Energy saving potentials related to steam generation and its usage in the medium size bakery are analyzed and presented. Input data needed for the investigation are gathered through detailed energy audit. Four energy savings measures are analysed in detail: 1) change of heat generator for space heating and domestic hot water preparation from steam boiler to condensing boiler, 2) reduction of heat losses from steam and condensate distribution lines, 3) heat utilization of return condensate and 4) replacement of the old, low efficiency steam boiler with high-efficient one. Implementation of these measures will result in substantial reduction of energy costs, ranging from 2.900 to 26.200 € annually. Interaction of all measures is analysed through energy efficiency improvement scenario, whose implementation will ensure significant energy cost savings, estimated at 40.793 € annually, with simple payback period shorter than 4 years. Implementation of presented measures will improve facility’s energy efficiency, represented through reduction of annual energy performance indicators by 6,14 %. Presented analysis revealed that steam generation and its usage in the industrial facilities offer a substantial potential for reduction of energy use and energy related cost.
This article introduces a computational design framework for obtaining three‐dimensional (3D) periodic elastoplastic architected materials with enhanced performance, subject to uniaxial or shear strain. A nonlinear finite element model accounting for plastic deformation is developed, where a Lagrange multiplier approach is utilized to impose periodicity constraints. The analysis assumes that the material obeys a von Mises plasticity model with linear isotropic hardening. The finite element model is combined with a corresponding path‐dependent adjoint sensitivity formulation, which is derived analytically. The optimization problem is parametrized using the solid isotropic material penalization method. Designs are optimized for either end compliance or toughness for a given prescribed displacement. Such a framework results in producing materials with enhanced performance through much better utilization of an elastoplastic material. Several 3D examples are used to demonstrate the effectiveness of the mathematical framework.
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