Adaptive Element Research Articles

Looking Back on the Actor–Critic Architecture

This retrospective describes the overall research project that gave rise to the authors’ paper “Neuronlike adaptive elements that can solve difficult learning control problems” that was published in the 1983 Neural and Sensory Information Processing special issue of the IEEE Transactions on Systems, Man, and Cybernetics. This look back explains how this project came about, presents the ideas and previous publications that influenced it, and describes our most closely related subsequent research. It concludes by pointing out some noteworthy aspects of this article that have been eclipsed by its main contributions, followed by commenting on some of the directions and cautions that should inform future research.

Nature-Inspired Algorithm Implemented for Stable Radial Basis Function Neural Controller of Electric Drive with Induction Motor

The main point of this paper was to perform the design process for and verify the properties of an adaptive neural controller implemented for a real nonlinear object—an electric drive with an Induction Motor (IM). The controller was composed as a parallel combination of the classical Proportional-Integral (PI) structure, and the second part was based on Radial Basis Function Neural Networks (RBFNNs) with the on-line recalculation of the weight layer. The algorithm for the adaptive element of the speed controller contained two parts in parallel. The first of them was dedicated for the main path of the neural network calculations. The second realized the equations of the adaptation law. The stability of the control system was provided according to the Lyapunov theorem. However, one of the main issues described in this work is the optimization of the constant part of the analyzed parallel speed controller. For this purpose, the Grey Wolf Optimizer (GWO) was applied. A deep analysis of the data processing during the calculations of this technique is shown. The implemented controller, based on the theory of neural networks, is an adaptive system that allows precise motor control. It ensures the precise and dynamic response of the electric drive. The theoretical considerations were firstly verified during the simulations. Then, experimental tests were performed (using a dSPACE1103 card and an induction machine with a rated power of 1.1 kW).

An adaptive edge element approximation of a quasilinear H(curl)-elliptic problem

An adaptive edge element method is designed to approximate a quasilinear [Formula: see text]-elliptic problem in magnetism, based on a residual-type a posteriori error estimator and general marking strategies. The error estimator is shown to be both reliable and efficient, and its resulting sequence of adaptively generated solutions converges strongly to the exact solution of the original quasilinear system. Numerical experiments are provided to verify the validity of the theoretical results.

Artificial Intelligence for Adaptive and Reconfigurable Antenna Arrays: A Review

This article provides an overview of a few applications of artificial intelligence (AI) in adaptive and reconfigurable antenna arrays. In particular, AI proves to be more robust than traditional approaches in noisy and high multipath environments compared to many signal processing algorithms. AI is highly dependent upon the array architecture and requires the signal control offered by digital beamforming. Five application areas are presented, including adaptive nulling, wireless localization, multiple-input, multiple-output (MIMO) communications, element failures, and calibration.

Adaptation, spatial effects, and targeting: Evidence from Africa and Asia

• The ability of farmers to adapt to changing environments is an important determinant of welfare. • Neighbors may enhance adaptive capacity through spatial spillover adaptation effects. • Spatial interactions amplify the marginal effects of adaptive capacity elements by 50 percent. • Targeting the adaptation of few but central households is enough to generate spatial spillovers. The ability of farmers to adapt to changing rural environments in developing countries is an important determinant of welfare. But the adaptive capacity of farmers may be constrained because economic resources, information, and institutions are often weak or missing. Farmers living close to one another face similar environmental and economic conditions, but may have different levels of adaptive capacity. These spatially connected farmers (or neighbors) can potentially ease economic constraints and facilitate adaptation by acting as conduits of information and resources. This paper estimates spatial effects on adaptation: how neighbors’ adaptations influence farmers’ adaptation decisions. Our data contains information from more than two thousand households located across 12 countries in Africa and Asia. We find that neighbors significantly influence adaptation decisions, and that spatial interactions amplify the marginal effects of adaptive capacity elements by 50 percent. We also propose a targeting approach that decomposes the total spatial effect into effects coming from different subsets of households that are selected according to their spatial centrality. We find that targeting the two households with highest eigenvector centrality in each village is enough to generate a statistically significant spatial multiplier effect.

Adaptive Elements in Internet-Delivered Psychological Treatment Systems: Systematic Review.

BackgroundInternet-delivered psychological treatments (IDPTs) are built on evidence-based psychological treatment models, such as cognitive behavioral therapy, and are adjusted for internet use. The use of internet technologies has the potential to increase access to evidence-based mental health services for a larger proportion of the population with the use of fewer resources. However, despite extensive evidence that internet interventions can be effective in the treatment of mental health disorders, user adherence to such internet intervention is suboptimal.ObjectiveThis review aimed to (1) inspect and identify the adaptive elements of IDPT for mental health disorders, (2) examine how system adaptation influences the efficacy of IDPT on mental health treatments, (3) identify the information architecture, adaptive dimensions, and strategies for implementing these interventions for mental illness, and (4) use the findings to create a conceptual framework that provides better user adherence and adaptiveness in IDPT for mental health issues.MethodsThe review followed the guidelines from Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The research databases Medline (PubMed), ACM Digital Library, PsycINFO, CINAHL, and Cochrane were searched for studies dating from January 2000 to January 2020. Based on predetermined selection criteria, data from eligible studies were analyzed.ResultsA total of 3341 studies were initially identified based on the inclusion criteria. Following a review of the title, abstract, and full text, 31 studies that fulfilled the inclusion criteria were selected, most of which described attempts to tailor interventions for mental health disorders. The most common adaptive elements were feedback messages to patients from therapists and intervention content. However, how these elements contribute to the efficacy of IDPT in mental health were not reported. The most common information architecture used by studies was tunnel-based, although a number of studies did not report the choice of information architecture used. Rule-based strategies were the most common adaptive strategies used by these studies. All of the studies were broadly grouped into two adaptive dimensions based on user preferences or using performance measures, such as psychometric tests.Conclusions Several studies suggest that adaptive IDPT has the potential to enhance intervention outcomes and increase user adherence. There is a lack of studies reporting design elements, adaptive elements, and adaptive strategies in IDPT systems. Hence, focused research on adaptive IDPT systems and clinical trials to assess their effectiveness are needed.

PHENOMENON OF DEVELOPMENT OF PROFESSIONAL COMPETENCE OF SOCIAL WORKERS IN RESEARCH OF DOMESTIC SCIENTISTS

The process of formation of professional competencies of social workers in Ukraine is an important aspect of their education in higher education institutions of Ukraine. The analyzed domestic scientific works allow us to conclude that the professional competencies of social workers are a complex structure and consist in addition to mastering practical and theoretical methods of social work of the following competencies: socio-emotional, socio-legal, psychological and life. Another important factor for the formation of professional competencies of modern social workers in Ukraine is the implementation of successful cases in various spheres of social life as an element of successful adaptation and self-realization to the conditions of direct activity in practical social work and increase the authority of social workers among clients of domestic social services and institutions. etc. The purpose of the article is to study the features of the phenomenon of formation of professional competence of social workers. General scientific and special research methods beame the theoretical and methodological basis for studying the peculiarities of the formation of professional competence of a social worker in domestic scientific works. In the course of the research the methods of historical, systemic and structural-functional analysis were used − for the theoretical analysis of the formation of professional competence; methods of analysis and synthesis − to clarify the genesis of the concept of «professional competence», its application in theoretical science and social practice; comparative analysis and methods of document analysis; method of classification and typology − to determine the types of competencies in domestic scientific works; comparative analysis of documents - to study the practices of using the concept of «professional competence of a social worker», etc. We have established that today in the process of organizing education in higher education it is important to change the priorities in the formation of professional competencies of social workers through the introduction of competency-based training of future social workers. It has been determined that the competencies of a social worker change over time. It is substantiated that the most important professional competencies of social workers are communicative, social and legal competencies, as well as methodological competencies in the field of social work with different groups of clients and psychological readiness to carry out direct professional activity.

Infrared small target detection via adaptive M-estimator ring top-hat transformation

Top-Hat transformation is an essential technology in the field of infrared small target detection. Many modified Top-Hat transformation methods have been proposed based on the different structure of structural elements. However, these methods are still hard to handle the dim targets and complex background. It can be summarized as two reasons, one is that the structural elements cannot suppress the background adaptively due to the fixed value of structural elements in image. Another is that simple structural element cannot utilize the local feature for target enhancement. To overcome these two limitations, a special ring Top-Hat transformation based on M-estimator and local entropy is proposed in this paper. First, an adaptive ring structural element based on M-estimator is used to suppress the complex background. Second, a novel local entropy is proposed to weight structural element for capturing local feature and target enhancement. Finally, a comparison experiment based on massive infrared image data (more than 500 infrared target images) is done. And the results demonstrate that the proposed algorithm acquires better performance compared with some recent methods.

Clothing of Arctic Nomads: Traditional Technologies and Ethnodesign

The article attempts to identify and structure ethnodesign's approaches to the study of traditional clothing of nomads of the Arctic, using the example of reindeer herders of Yamal (Nenets) and Chaun-Chukotka (Chukchi). As the research shows, the material world of a nomad reindeer herder exists in the system of a “nomadic transformer”, i.e. it is defined by and subordinated to the cycles of nomadic variability in space-time rhythms and dimensions, states of statics and dynamics, and communication with other communities. Quality and properties of clothing, as one of the main elements of adaptation to a nomadic lifestyle, are fully manifested in the dynamics: it is born and transformed and it dies in motion. The practices of making, wearing and using, repairing and disposing of clothing are organically intertwined with the rhythms of nomadism. The approaches to the study of Arctic nomads' clothing presented in the article - microstructural and bio-physiological, mim-adaptive and technological, gender-ethnocultural, and mobile-transformation - focus on the natural development of traditional technologies and work in motion. In combination, they allow us to look at nomad fur clothing from different angles and with different degree of approximation - from microstructural properties of reindeer hair and options of adaptational mimicry to an analysis of constructural and technological, gender and ethno-cultural features.

Preload Control of Spindle Bearings by Means of Shape Memory Alloys

Commercial, motor-driven spindles for applications in machine tools are generally developed for specific machining operations. Spindles can be distinguished between spindles for HPC (High Performance Cutting) and spindles for HSC (High Speed Cutting). HPC and HSC require opposing specifications concerning motor configuration and the preload of the spindle bearings. To realize a universal machine tool spindle, changeable motor configuration and preload of the spindle bearings are necessary. In this paper, a new approach for an adaptive preload element is presented to control the preload of a spindle bearing arrangement. The adaptive preload element consists of actuators based on shape memory alloys in combination with Peltier elements. By controlling the current through the Peltier elements the temperature of shape memory alloys bending springs is controlled. Thus, the preload force of the bending springs can be variated. Experimental tests reveal the properties of the preload element and its suitability for preload modification. Within these tests, the adaptive preload element enables a preload modification of about 850 N.

ESTIMATION OF HEAT RESISTANCE OF OILSEED RADISH BY LABORATORY METHODS

The article reflects the results of studying the peculiarities of the study of drought and heat resistance of three zoned varieties of oil radish, based on widely tested methods applied to a number of other agricultural crops. The viewpoints of many researchers on the processes of forming the temperature stress adaptations of plants have been systematised, taking into consideration the mechanism of drought and heat resistance and its role in providing the development of adaptive elements of the technology for growing cruciferous crops and climatic changes in the growing season in the area of economic distribution of oilseed radish. The peculiarities of the application of two laboratory techniques simultaneously have been studied. One of the methods is based on stress reactions of seeds with an assessment of the level of its germination after preliminary long-term heating of the wetted seeds by gradually increasing high temperatures. The second technique is based on the temperature reaction of the assimilation apparatus of plants to an environment with different temperatures in order to determine the degree of destructive effect of high temperatures on leaf structures with the subsequent determination of the degree of damage to the studied samples by staining the affected areas in the appropriate chemical environments. The application of this methodology has made it possible to determine that the threshold temperature value for forming the standard permissible levels of laboratory germination of seeds in the studied varieties of oil radish is in the range of 35-45 °C. The actual intensive decrease in laboratory germination for seeds with one-year biological age in the studied varieties of oil radish has been distinguished for the temperature regime of heating at 60 °C and higher with a zero level of laboratory germination at 80 °C. Considering the short heating period of pre-soaked seeds, oil radish plants are able to withstand a short-term increase in air temperature with sufficient soil moisture in the confidence range of 40-55 °C. Considering the decrease in laboratory germination for seeds of biological age 1-5 years already starting from the level of preliminary heating at a temperature of 30 °C – the optimum germination of oilseed radish varieties and the optimal growth and development of oilseed radish plants in conditions of sufficient soil moisture was most likely in the range of 20-25°C. Based on the results of the application of these methods in relation to drought and heat resistance, the studied varieties of oilseed radish can be placed in the following order of decreasing of the indicator ‘Raduga’-‘Zhuravka’-‘Lybid’. The prospects for further research in the field of optimizing drought and heat resistance diagnostics by laboratory methods have been formulated. Key words: oilseed radish, drought resistance, heat resistance, germination, temperature adaptation.

An adaptive shell element for explicit dynamic analysis of failure in laminated composites Part 2: Progressive failure and model validation

To enable modelling of the progressive failure of large, laminated composite components under crash or impact loading, it is key to have a numerical methodology that is both efficient and numerically robust. A potential way is to adopt an adaptive method where the structure is initially represented by an equivalent single-layer shell model, which during the analysis is adaptively transformed to a high-resolution layer-wise model in areas where higher accuracy is required. Such a method was recently developed and implemented in the commercial finite element solver LS-DYNA, aiming at explicit crash analysis (Främby, Fagerström and Karlsson: An adaptive shell element for explicit dynamic analysis of failure in laminated composites - Part 1: Adaptive kinematics and numerical implementation, 2020). In the current work, the method is extended to the case of interacting inter- and intralaminar damage evolution. As a key part, we demonstrate the importance of properly regularising the intralaminar failure described by a smeared-crack model, and show that neglecting to account for the crack-versus-mesh orientation may lead to significant errors in the predicted energy dissipation. We also validate the adaptive approach against a four-point beam bending test with matrix-induced delamination growth, and simultaneously show the capability of the proposed method to – at lower computational expense – replicate the results from a refined, non-adaptive model.

Enhanced Pseudo-Three-Dimensional Model for Multiple Hydraulic Fractures

Abstract Modeling the propagation of hydraulic fractures is a complex problem that involves solving the equations that describe the intimate coupling between the cracked and porous solid phase and the fracturing fluid that drives the process according to established crack extension criteria. Most of the existing computational techniques become prohibitively expensive if applied to three-dimensional configurations, especially those involving multiple fractures because their accuracy relies on extremely fine discretizations of the geometry. These include the standard finite element method and standard displacement discontinuity method, which require substantial mesh densities in the vicinity of the crack front to capture the complex nature of the singular fields associated with fluid-driven cracks. Models have recently been proposed that offer sufficient accuracy and a significant increase in computational efficiency. These include the enhanced pseudo-3D model that explicitly incorporates a non-local elasticity relation and known crack-front asymptotic solutions that capture the multiscale near-front behavior. Here, we present an enhanced pseudo-3D model for simulating the propagation of multiple planar and nonplanar hydraulic fractures in a linear elastic medium. The algorithm is built on a fixed mesh with an adaptive tip element, and it incorporates leak-off, as well as stress interaction between the fractures. The model is validated against reference solutions of plane strain, radial, and multi-planar fracture geometries, for various sets of parameters that cover the majority of the problem parametric space.

The Role of Microbiota in Neutrophil Regulation and Adaptation in Newborns.

Newborns are highly susceptible to infections and mainly rely on innate immune functions. Reduced reactivity, delayed activation and subsequent failure to resolve inflammation however makes the neonatal immune system a very volatile line of defense. Perinatal microbiota, nutrition and different extra-uterine factors are critical elements that define long-term outcomes and shape the immune system during the neonatal period. Neutrophils are first responders and represent a vital component of the immune system in newborns. They have long been regarded as merely executive immune cells, however this notion is beginning to shift. Neutrophils are shaped by their surrounding and adaptive elements have been described. The role of “innate immune memory” and the main triangle connection microbiome—neutrophil—adaptation will be discussed in this review.

Microscope-AOtools: a generalised adaptive optics implementation.

Aberrations arising from sources such as sample heterogeneity and refractive index mismatches are constant problems in biological imaging. These aberrations reduce image quality and the achievable depth of imaging, particularly in super-resolution microscopy techniques. Adaptive optics (AO) technology has been proven to be effective in correcting for these aberrations, thereby improving the image quality. However, it has not been widely adopted by the biological imaging community due, in part, to difficulty in set-up and operation of AO. The methods for doing so are not novel or unknown, but new users often waste time and effort reimplementing existing methods for their specific set-ups, hardware, sample types, etc. Microscope-AOtools offers a robust, easy-to-use implementation of the essential methods for set-up and use of AO elements and techniques. These methods are constructed in a generalised manner that can utilise a range of adaptive optics elements, wavefront sensing techniques and sensorless AO correction methods. Furthermore, the methods are designed to be easily extensible as new techniques arise, leading to a streamlined pipeline for new AO technology and techniques to be adopted by the wider microscopy community.

An adaptive shell element for explicit dynamic analysis of failure in laminated composites Part 1: Adaptive kinematics and numerical implementation

To introduce more fibre-reinforced polymers in cars, the automotive industry is strongly dependent on efficient modelling tools to predict the correct energy absorption in crash simulations. In this context, an adaptive modelling technique shows great potential. However, as the critical energy absorption in a crash occurs over a very short period of time, and since the deformation behaviour is very complex, car crash simulations are usually performed using explicit dynamic finite element solvers. Therefore, any practical adaptive technique must be adapted to an explicit setting in a software available to the automotive companies. In this paper, we propose an adaptive method for explicit finite element analysis and describe its implementation in the commercial finite element solver LS-DYNA. The method allows for both so-called weak discontinuities (discontinuities in strain), which are crucial for accurate stress and intralaminar damage predictions, and strong discontinuities (discontinuities in displacements), needed for a proper representation of growing delamination cracks. In particular, we detail the implementation of the proposed method into LS-DYNA and also how we propose to remedy the non-physical oscillations arising from the implementation of the adaptive scheme in a explicit dynamic setting. The paper is concluded with numerical examples where we demonstrate the potential for the adaptive approach and also perform a detailed study on its accuracy and stability.

ARCHITECTONICS OF ADAPTIVE MECHANISM MANAGEMENT OF SUSTAINABLE ECONOMIC DEVELOPMENT OF AGRICULTURAL PRODUCTION

Introduction. The current state of the environment, which is determined by the challenges of sustainable economic development, has become an objective basis for the statement: ensuring the successful operation of enterprises (increasing competitiveness and strengthening their potential) is not possible without external factors and rapid response to their changes, the formation of adaptive management mechanisms that can ensure the transition of agricultural enterprises to the trajectory of sustainable economic development. The purpose of the article is to offer the architectonics of the adaptive mechanism of management of sustainable economic development of agricultural production and to substantiate its main elements. Results. It is substantiated that the instrumental content of the activities of the environment includes mechanisms of direct influence (legislative and regulatory framework, implementation of government programs and investment projects, tariff restrictions, non-tariff restrictions) and indirect influence (processes of effective demand; instruments of competitive interaction; price mechanism; contract system, infrastructure development, intangible instruments, monetary, financial, social policy, financial assistance). The use of the software product TextAnalyst allowed to formulate generalized definitions of the category of control mechanism (a set of interrelated forms, methods, tools of purposeful influence on the object of management to achieve certain goals). An adaptive mechanism for managing sustainable economic development of agricultural production based on the "white box" method has been developed. The latter is represented by a block of input streams, object structure of influence, output streams. It is established that the current state of agricultural production and its ability to change is determined by the internal system of adaptation mechanism in the complex interaction of adaptive potential, adaptation process, adaptation capabilities, elements of adaptation, attractors, bifurcation points, adaptation vector. Key words: adaptability, management mechanism, management tools, sustainable economic development, agricultural production.

Transcriptional Enhancers in Drosophila.

Key discoveries in Drosophila have shaped our understanding of cellular “enhancers.” With a special focus on the fly, this chapter surveys properties of these adaptable cis-regulatory elements, whose actions are critical for the complex spatial/temporal transcriptional regulation of gene expression in metazoa. The powerful combination of genetics, molecular biology, and genomics available in Drosophila has provided an arena in which the developmental role of enhancers can be explored. Enhancers are characterized by diverse low- or high-throughput assays, which are challenging to interpret, as not all of these methods of identifying enhancers produce concordant results. As a model metazoan, the fly offers important advantages to comprehensive analysis of the central functions that enhancers play in gene expression, and their critical role in mediating the production of phenotypes from genotype and environmental inputs. A major challenge moving forward will be obtaining a quantitative understanding of how these cis-regulatory elements operate in development and disease.

Optomechanically Actuated Microcilia for Locally Reconfigurable Surfaces.

Artificial microcilia structures have shown potential to incorporate actuators in various applications such as microfluidic devices and biomimetic microrobots. Among the multiple possibilities to achieve cilia actuation, magnetic fields present an opportunity given their quick response and wireless operation, despite the difficulty in achieving localized actuation because of their continuous distribution. In this work, a high-aspect-ratio (>8), elastomeric, magnetically responsive microcilia array is presented that allows for wireless, localized actuation through the combined use of light and magnetic fields. The microcilia array can move in response to an external magnetic field and can be locally actuated by targeted illumination of specific areas. The periodic pattern of the microcilia also diffracts light with varying diffraction efficiency as a function of the applied magnetic field, showing potential for wirelessly controlled adaptive optical elements.

Health effects of heating, ventilation and air conditioning on hospital patients: a scoping review

BackgroundIn the face of climate change, the protection of vulnerable patients from extreme climatic conditions is of growing interest to the healthcare sector and governments. Inpatients are especially susceptible to heat due to acute illness and/or chronic diseases. Their condition can be aggravated by adverse environmental factors. Installing air conditioning can be seen as an element of public health adaptation because it was shown to improve mortality rates of hospital patients experiencing hot temperatures. Still, the mediating factors and resulting health effects are largely unknown.MethodThe PRISMA-ScR guideline was followed for this scoping review. Available evidence on the health effects of Heating, Ventilation, Air Conditioning (HVAC) and fans was searched in Medline, Embase and the Cochrane Library. The focus of the search strategy was on inpatients of the hospital. Grey literature was screened on 14 relevant websites. English and German publications were eligible without restrictions on publication date. Results were charted according to the categories population, intervention, control and outcome together with a qualitative description.ResultsThe review process yielded eleven publications of which seven were issued after 2003. Seven were clinical trials, three cross-sectional studies and one was a case report. The publications described the installation of HVAC on general wards and in intensive care units. Main topics were heat stress protection and support of thermoregulation, but also the rewarming of hypothermic patients. HVAC use resulted in a recovery effect shown by improved vital signs, reduced cardiac stress, accelerated recuperation and greater physical activity. This protective effect was demonstrated by a shorter hospital stay for patients with respiratory disease and a reduction of mortality for heat illness patients.ConclusionThis scoping review summarises the fragmented evidence on health effects of HVAC and fan utilisation for inpatients. Installing HVAC has the potential to improve patients’ outcomes and to make hospital treatment more efficient during heat waves. The application of HVAC could be a promising adaptation measure to mitigate the adverse effects of climate change on health and healthcare systems.