scholarly journals Online learning for orientation estimation during translation in an insect ring attractor network

2021 ◽  
Author(s):  
Brian S Robinson ◽  
Raphael Norman-Tenazas ◽  
Martha Cervantes ◽  
Danilo Symonette ◽  
Erik C Johnson ◽  
...  
Keyword(s):  
Estimation Error ◽  
Central Complex ◽  
Robotic Systems ◽  
Orientation Estimation ◽  
Theoretical Understanding ◽  
Neural Imaging ◽  
Physical Environments ◽  
Underlying Mechanisms ◽  
Network Weight ◽  
Promising Source

Insect neural systems are a promising source of inspiration for new algorithms for navigation, especially on low size, weight, and power platforms. There have been unprecedented recent neuroscience breakthroughs with Drosophila in behavioral and neural imaging experiments as well as the mapping of detailed connectivity of neural structures. General mechanisms for learning orientation in the central complex (CX) of Drosophila have been investigated previously; however, it is unclear how these underlying mechanisms extend to cases where there is translation through an environment (beyond only rotation), which is critical for navigation in robotic systems. Here, we develop a CX neural connectivity-constrained model that performs sensor fusion, as well as unsupervised learning of visual features for path integration; we demonstrate the viability of this circuit for use in robotic systems in simulated and physical environments. Furthermore, we propose a theoretical understanding of how distributed online unsupervised network weight modification can be leveraged for learning in a trajectory through an environment by minimizing of orientation estimation error. Overall, our results here may enable a new class of CX-derived low power robotic navigation algorithms and lead to testable predictions to inform future neuroscience experiments.

Model-based Head Orientation Estimation for Smart Devices

2021 ◽  
Vol 5 (3) ◽  
pp. 1-24
Author(s):  
Qiang Yang ◽  
Yuanqing Zheng
Keyword(s):  
Radiation Pattern ◽  
Microphone Array ◽  
Estimation Error ◽  
Microphone Arrays ◽  
Smart Devices ◽  
Head Orientation ◽  
Context Information ◽  
Orientation Estimation ◽  
Model Based ◽  
The Voice

Voice interaction is friendly and convenient for users. Smart devices such as Amazon Echo allow users to interact with them by voice commands and become increasingly popular in our daily life. In recent years, research works focus on using the microphone array built in smart devices to localize the user's position, which adds additional context information to voice commands. In contrast, few works explore the user's head orientation, which also contains useful context information. For example, when a user says, "turn on the light", the head orientation could infer which light the user is referring to. Existing model-based works require a large number of microphone arrays to form an array network, while machine learning-based approaches need laborious data collection and training workload. The high deployment/usage cost of these methods is unfriendly to users. In this paper, we propose HOE, a model-based system that enables Head Orientation Estimation for smart devices with only two microphone arrays, which requires a lower training overhead than previous approaches. HOE first estimates the user's head orientation candidates by measuring the voice energy radiation pattern. Then, the voice frequency radiation pattern is leveraged to obtain the final result. Real-world experiments are conducted, and the results show that HOE can achieve a median estimation error of 23 degrees. To the best of our knowledge, HOE is the first model-based attempt to estimate the head orientation by only two microphone arrays without the arduous data training overhead.

scholarly journals Animal activity around the clock with no overt circadian rhythms: patterns, mechanisms and adaptive value

2013 ◽  
Vol 280 (1765) ◽  
pp. 20130019 ◽  
Author(s):  
Guy Bloch ◽  
Brian M. Barnes ◽  
Menno P. Gerkema ◽  
Barbara Helm
Keyword(s):  
Circadian Rhythms ◽  
Activity Patterns ◽  
Polar Regions ◽  
Life History Stages ◽  
Adaptive Value ◽  
Physical Environments ◽  
Trade Offs ◽  
Animal Activity ◽  
Underlying Mechanisms ◽  
Organizational Principles

Circadian rhythms are ubiquitous in many organisms. Animals that are forced to be active around the clock typically show reduced performance, health and survival. Nevertheless, we review evidence of animals showing prolonged intervals of activity with attenuated or nil overt circadian rhythms and no apparent ill effects. We show that around-the-clock and ultradian activity patterns are more common than is generally appreciated, particularly in herbivores, in animals inhabiting polar regions and habitats with constant physical environments, in animals during specific life-history stages (such as migration or reproduction), and in highly social animals. The underlying mechanisms are diverse, but studies suggest that some circadian pacemakers continue to measure time in animals active around the clock. The prevalence of around-the-clock activity in diverse animals and habitats, and an apparent diversity of underlying mechanisms, are consistent with convergent evolution. We suggest that the basic organizational principles of the circadian system and its complexity encompass the potential for chronobiological plasticity. There may be trade-offs between benefits of persistent daily rhythms versus plasticity, which for reasons still poorly understood make overt daily arrhythmicity functionally adaptive only in selected habitats and for selected lifestyles.

scholarly journals DRIVERS AND CONSEQUENCES OF BUSINESS-REFERENCE-CONTENT (BRC): THE ROLE OF NARRATIVE TRANSPORTATION IN B2B COMMUNICATION

2021 ◽  
Vol 22 (5) ◽  
pp. 1323-1341
Author(s):  
Chang Mo Jung
Keyword(s):  
Purchase Intention ◽  
Financial Risk ◽  
Online Survey ◽  
Theoretical Understanding ◽  
B2b Marketing ◽  
Narrative Transportation ◽  
Transportation Theory ◽  
Narrative Format ◽  
Underlying Mechanisms ◽  
Potential Customers

COVID-19 is bringing changes in B2B sales and marketing strategies. Digital interaction with potential customers has become more critical. Business-reference content (BRC) is the most shared content, mainly using narrative format, available to potential customers through digital touchpoints. Reducing perceived purchasing risk has been recognized as the primary benefit of using BRC, but empirical research on this has been insufficient. Therefore, this research investigated the underlying mechanisms of BRC and related processes that lower risk perception based on narrative transportation theory. For empirical analysis, a serial-parallel mediating model was established in which BRC type (narrative versus non-narrative) influences purchase intention through the mediation of narrative transportation and perceived purchase risks – functional risk and financial risk. In this experimental study, an online survey was conducted in which 233 purchasing managers in Korean companies participated. The analysis confirmed that the BRC type had a significant effect on the level of receivers’ narrative transportation. In addition, serial-parallel mediating effects through narrative transportation (primary mediator) and perceived functional risk and perceived financial risk (secondary mediators) were all significant. This research provides meaningful implications in that it broadens the theoretical understanding of BRC by presenting the integrated BRC effect model. Also, it clarifies the importance of narrative BRC in B2B marketing practices.

Honor the old, welcome the new: an account of unlearning and forgetting in NPD teams

2019 ◽  
Vol 23 (4) ◽  
pp. 581-603 ◽  
Author(s):  
Adrian Klammer ◽  
Stefan Gueldenberg
Keyword(s):  
Empirical Evidence ◽  
New Product Development ◽  
Structured Interviews ◽  
Holistic Model ◽  
Theoretical Understanding ◽  
Knowledge Loss ◽  
Content Type ◽  
Team Members ◽  
Underlying Mechanisms ◽  
Levers Of Control

Purpose The purpose of this paper is to empirically investigate the antecedents, levers of control and outcomes of organizational unlearning and forgetting in new product development (NPD) teams. Design/methodology/approach This paper employs a holistic multiple-case study design. This paper gathered data from 30 individual semi-structured interviews in 10 different NPD teams as well as additional data to triangulate the findings. Findings The authors propose a model of unlearning and forgetting elements occurring in NPD teams. The two most prominent factors that hamper innovation are the inability to unlearn and involuntary forgetting. Failure to manage these antecedents results in the loss of crucial resources, missing innovations or intra-team tensions. Managing knowledge loss by promoting unlearning and reducing forgetting leads to enhanced creativity and flexibility, a higher chance of exceeding innovation goals, increased conversion efficiency and augmentation of existing knowledge. Research limitations/implications This paper contributes empirical evidence to the field of unlearning and forgetting. The model illustrates the NPD process from the perspective of organizational unlearning and forgetting. The authors examined the NPD process from an unlearning and forgetting perspective and proposed new categories of antecedents, consequences and managing unlearning and forgetting. This generates a more profound theoretical understanding of underlying knowledge loss processes in NPD teams. Practical implications Companies should promote unlearning and specify spatial and temporal freedom. In doing so, team members can identify outdated and obsolete knowledge. Being attentive to unlearning and forgetting processes allows teams to achieve increased creativity and flexibility. Originality/value This paper provides empirical evidence to generate a more profound understanding of the underlying mechanisms of knowledge loss in NPD teams. First, the authors propose a holistic model of antecedents, levers of control and consequences of both unlearning and forgetting. Second, the authors suggest that organizations can use these levers of control to successfully manage unlearning and forgetting in NPD teams.

scholarly journals Senescence in Bacteria and Its Underlying Mechanisms

2021 ◽  
Vol 9 ◽  
Author(s):  
Ulrich Karl Steiner
Keyword(s):  
Environmental Conditions ◽  
Inclusion Bodies ◽  
Biological Organization ◽  
Experimental Conditions ◽  
Theoretical Understanding ◽  
Growth And Survival ◽  
Daughter Cells ◽  
Theories Of Aging ◽  
Underlying Mechanisms ◽  
A Chain

Bacteria have been thought to flee senescence by dividing into two identical daughter cells, but this notion of immortality has changed over the last two decades. Asymmetry between the resulting daughter cells after binary fission is revealed in physiological function, cell growth, and survival probabilities and is expected from theoretical understanding. Since the discovery of senescence in morphologically identical but physiologically asymmetric dividing bacteria, the mechanisms of bacteria aging have been explored across levels of biological organization. Quantitative investigations are heavily biased toward Escherichia coli and on the role of inclusion bodies—clusters of misfolded proteins. Despite intensive efforts to date, it is not evident if and how inclusion bodies, a phenotype linked to the loss of proteostasis and one of the consequences of a chain of reactions triggered by reactive oxygen species, contribute to senescence in bacteria. Recent findings in bacteria question that inclusion bodies are only deleterious, illustrated by fitness advantages of cells holding inclusion bodies under varying environmental conditions. The contributions of other hallmarks of aging, identified for metazoans, remain elusive. For instance, genomic instability appears to be age independent, epigenetic alterations might be little age specific, and other hallmarks do not play a major role in bacteria systems. What is surprising is that, on the one hand, classical senescence patterns, such as an early exponential increase in mortality followed by late age mortality plateaus, are found, but, on the other hand, identifying mechanisms that link to these patterns is challenging. Senescence patterns are sensitive to environmental conditions and to genetic background, even within species, which suggests diverse evolutionary selective forces on senescence that go beyond generalized expectations of classical evolutionary theories of aging. Given the molecular tool kits available in bacteria, the high control of experimental conditions, the high-throughput data collection using microfluidic systems, and the ease of life cell imaging of fluorescently marked transcription, translation, and proteomic dynamics, in combination with the simple demographics of growth, division, and mortality of bacteria, make the challenges surprising. The diversity of mechanisms and patterns revealed and their environmental dependencies not only present challenges but also open exciting opportunities for the discovery and deeper understanding of aging and its mechanisms, maybe beyond bacteria and aging.

Bond Graph Based Approach to Passive Teleoperation of a Hydraulic Backhoe

2005 ◽  
Vol 128 (1) ◽  
pp. 176-185 ◽  
Author(s):  
Kailash Krishnaswamy ◽  
Perry Y. Li
Keyword(s):  
Passive Control ◽  
Force Feedback ◽  
Haptic Feedback ◽  
Past Research ◽  
Bond Graph ◽  
Robotic Systems ◽  
Control Law ◽  
Coordination Control ◽  
Physical Environments ◽  
And Performance

Human operated, hydraulic actuated machines are widely used in many high-power applications. Improving productivity, safety and task quality (e.g., haptic feedback in a teleoperated scenario) has been the focus of past research. For robotic systems that interact with the physical environments, passivity is a useful property for ensuring safety and interaction stability. While passivity is a well utilized concept in electromechanical robotic systems, investigation of electrohydraulic control systems that enforce this passivity property are rare. This paper proposes and experimentally demonstrates a teleoperation control algorithm that renders a hydraulic backhoe/force feedback joystick system as a two-port, coordinated, passive machine. By fully accounting for the fluid compressibility, inertia dynamics and nonlinearity, coordination performance is much improved over a previous scheme in which the coordination control approximates the hydraulic system by its kinematic behavior. This is accomplished by a novel bond graph based three step design methodology: (1) energetically invariant transformation of the system into a pair of “shape” and “locked” subsystems; (2) inversion of the shape system bond graph to derive the coordination control law; (3) use of the locked system bond graph to derive an appropriate control law to achieve a target locked system dynamics while ensuring the passivity property of the coordinated system. The proposed passive control law has been experimentally verified for its bilateral energy transfer ability and performance enhancements.

scholarly journals Are Absence and Limbic Seizures Mutually Exclusive?: An Experimental Approach to Enigmatic Clinical Concept

2021 ◽  
Vol 10 (02) ◽  
pp. 045-050
Author(s):  
Filiz Yılmaz Onat ◽  
Esat Eşkazan
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Experimental Approach ◽  
Mesial Temporal Lobe Epilepsy ◽  
Theoretical Understanding ◽  
Limbic Seizures ◽  
Mesial Temporal Lobe ◽  
Clinical Questions ◽  
Underlying Mechanisms ◽  
Clinical Concept

AbstractThe impressive advances in the several disciplines including neurophysiology, molecular biology, neuroimmunology, neurogenetics, neuroimaging, and neuropharmacology of epilepsies have been stimulating a mutual interaction among basic scientists, clinicians, and professionals from other disciplines, leading to the identification of clinical questions and then the design of basic science paradigms to test enigmatic clinical issues. Based on a clinical observation that the coexistence of genetic (idiopathic) generalized typical absence and mesial temporal lobe epilepsy in the same patient is extremely rare and debatable, we addressed the rare coexistence in the same individual, designed an experimental approach to test the validity of this clinical concept and to study the underlying mechanisms involved. Here we presented evidence of a mutual cross-interaction in the circuits involved in typical absence and temporal lobe epilepsy. This article delineates a phenomenological picture and comprehends a theoretical understanding of a mutual cross-interaction in typical absence as a representative of genetic generalized epilepsies and limbic epilepsy in which seizures often start from the mesial temporal lobe.

Participatory Methods for Entertainment–Education: Analysis of Best Practices

2017 ◽  
Vol 12 (1) ◽  
pp. 62-76 ◽  
Author(s):  
Amy Henderson Riley ◽  
Suruchi Sood ◽  
Meagan Robichaud
Keyword(s):  
Social Change ◽  
Best Practices ◽  
Current Theory ◽  
Participatory Methods ◽  
Entertainment Education ◽  
Theoretical Understanding ◽  
Wide Range ◽  
Comprehensive Search ◽  
Underlying Mechanisms ◽  
Communication Approach

Entertainment-education (EE) projects combine entertainment and education to increase knowledge, shift attitudes and promote social change using a range of communication platforms including theatre, radio, television, games, social media and others. Theoretical understanding regarding the underlying mechanisms of this creative communication approach developed alongside evidence and best practices for designing, implementing and evaluating interventions using techniques that reflect the current state of the field. Recent best practices often utilize participatory methods, a bottom-up approach wherein researchers work with stakeholders to identify culturally relevant indicators of change and gather information about the assets and needs of affected communities. Despite calls in the literature for reporting on participatory processes for health communication, a synthesis of such methods specific to EE has yet to emerge in the published literature. This comprehensive search reviews participatory best practices specifically used for the development and implementation of EE interventions with a wide range of behaviour and social change objectives. Findings suggest utilizing participatory research methods provide unique opportunities for inquiry aligned with current theory and evidence for both EE interventions and across other creative communication strategies. Implications include programmes produced by and with an audience as opposed to for an audience.

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