Feedback Flow Research Articles

Students’ perceptions of online peer feedback in process-oriented L2 writing: A qualitative inquiry

Peer feedback has been of paramount importance in second language (L2) writing given that L2 learners especially need the facilitative role of feedback in improving their writing skills. Despite recent research highlighting the benefits of peer feedback in L2 writing, there is a call for more qualitative studies situated in classroom contexts to explore the continuous flow of peer feedback in a social community including technology-enhanced interactive social settings. This case study takes the students at a university in Turkey as the center of the peer feedback process and explores how L2 writers (n = 35) using student blogs for online peer evaluation in the naturalistic setting of an academic writing course perceive online peer feedback in L2 writing. This qualitative study adopted a case study design using the data from students’ essays (210 essays), blog-mediated peer comments (on 35 student blogs), and self-reflection papers (105 reflections). The data was analyzed through Braun and Clarke’s inductive thematic analysis. The analysis resulting in four themes revealed that peer feedback experienced in an online writing community improved students’ ability to perceive and use feedback effectively by creating opportunities for a shared understanding of peer feedback and establishing a writing community and also enhanced students’ critical thinking skills as an essential aspect of the writing process. This study provides insights into the student experience of online peer feedback in L2 writing, highlighting the importance of creating a supportive and collaborative learning environment to foster effective feedback practices and enhance the students’ L2 writing skills.

Experimental closed-loop flow separation control: Data- and phenomenological-driven approaches

Flow control aims at modifying a natural flow state to reach an other flow state considered as advantageous. In this paper, active feedback flow separation control is investigated with two different closed-loop control strategies, involving a reference signal tracking architecture. Firstly, a data-driven control law, leading to a linear (integral) controller is employed. Secondly, a phenomenological/model-driven approach, leading to a non-linear positive (integral) control strategy is investigated. While the former benefits of a tuning simplicity, the latter prevents undesirable effects and formally guarantees closed-loop stability. Both control approaches were validated through wind tunnel experiments of flow separation control over a movable NACA 4412 plain flap. These control laws were designed with respect to hot-film measurements, performed over the flap for different deflection angles. Both control approaches proved efficient in avoiding flow separation. The main contribution of this work stands in providing practitioners, simple but yet efficient control design methods for the flow separation phenomena. Equivalently important, a complete validation campaign data-set is also provided.

Deep cavity noise suppression by exploiting aeroacoustic–structural interaction of multiple elastic panels

This paper reports a numerical study of a novel methodology for passive suppression of deep cavity noise by means of strategically designed and arrangements of multiple elastic panels and examines its underlying aeroacoustic–structural interaction physics. The study is conducted with a freestream, at Mach number 0.09 and Reynolds number of 4 × 104 based on the cavity length, past a two-dimensional cavity by means of direct aeroacoustic simulation coupled with a panel dynamic solver in monolithic fashion. For each cavity-panel configuration, the fluid-loaded panel natural frequencies are harmonized with the characteristic aeroacoustic processes of the original/modified cavity aeroacoustic feedback loop. This promotes panel aeroacoustic-structural resonance for absorption of feedback flow and acoustic fluctuation energy for achieving less eventual cavity noise. The most effective configuration gives a remarkable noise power reduction by 15 dB from a rigid cavity. Inadvertently, it reduces cavity drag by almost 15%. Simultaneous reduction of both cavity noise and drag is unprecedented among similar attempts in the literature. In-depth spatiotemporal analyses of aeroacoustic–structural interaction results elucidate the intricate interplay between cavity flow, panel vibration responses, and cavity acoustic modes, leading to noise reduction in all cavity-panel configurations studied. Essentially, the vertical panel acts to curtail the efficacy of coupling between growing shear layer and cavity acoustic modes whose sustenance is further impeded by an acoustically induced resonant panel at the cavity bottom. The proposed methodology is confirmed to be feasible yet effective, which holds great potential for fluid-moving applications in which a quiet and energy-efficient cavity configuration is desired.

Feedback flow control on a plunging circular cylinder

Feedback flow control on a plunging circular cylinder

Connectivity Matrix Seriation via Relaxation.

Volume electron microscopy together with computer-based image analysis are yielding neural circuit diagrams of ever larger regions of the brain. These datasets are usually represented in a cell-to-cell connectivity matrix and contain important information about prevalent circuit motifs allowing to directly test various theories on the computation in that brain structure. Of particular interest are the detection of cell assemblies and the quantification of feedback, which can profoundly change circuit properties. While the ordering of cells along the rows and columns doesn't change the connectivity, it can make special connectivity patterns recognizable. For example, ordering the cells along the flow of information, feedback and feedforward connections are segregated above and below the main matrix diagonal, respectively. Different algorithms are used to renumber matrices such as to minimize a given cost function, but either their performance becomes unsatisfying at a given size of the circuit or the CPU time needed to compute them scales in an unfavorable way with increasing number of neurons. Based on previous ideas, I describe an algorithm which is effective in matrix reordering with respect to both its performance as well as to its scaling in computing time. Rather than trying to reorder the matrix in discrete steps, the algorithm transiently relaxes the integer program by assigning a real-valued parameter to each cell describing its location on a continuous axis ('smooth-index') and finds the parameter set that minimizes the cost. I find that the smooth-index algorithm outperforms all algorithms I compared it to, including those based on topological sorting.

Numerical parametric study of a sweeping-vortex low-frequency fluidic oscillator

Fluidic oscillators are garnering increasing attention in various fields due to their self-induced oscillation characteristics. This study proposes a novel fluidic oscillator, the sweeping-vortex fluidic oscillator (SVFO), characterized by unique feedback properties. These properties exploit fluid feedback from the side opposite the attached wall and the spin delay of the captive vortex to yield low-frequency oscillating jets. The oscillation characteristics and the influence of main geometric parameters were investigated using computational fluid dynamics approach. Results show that the evolution of the flow field within the SVFO demonstrates an intricately dynamic interacting. The deflection switching of the main jet is primarily controlled by a pair of counter-rotating moving vortexes. Geometric parameters influence the stability of the dynamic evolution of both captive and moving vortexes, thereby altering the signal components of the output performance transmitted to the inlet. The overall width of the oscillator has a pronounced impact on the oscillation frequency, and with an increase in the overall width, a maximum frequency increase of 87 % can be observed. Furthermore, the height of the sweeping chamber and the diameter of the vortex chamber outlet have a noticeable effect on the pressure pulse amplitude. A pressure fluctuation coefficient greater than 1.1 was recorded. The results also suggest that the geometric parameters of the fluidic oscillator need to be designed within a reasonable range; otherwise, the jet oscillator will not function. A more refined optimization of geometric parameters could be obtained with the aim of achieving a stable main jet, feedback flow of appropriate intensity, and optimal attachment conditions. This work reveals the oscillation mechanism and the influence of geometric parameters on SVFOs, providing a theoretical basis for designing related oscillators.

Thematic analysis of circular economy practices across closed-loop supply chains: An institutional theory perspective

A circular economy (CE) presents an alternative solution to the scarcity of natural resources and environmental concerns. Institutional pressures motivate adopting and developing CE practices in various supply chain stages (SC), and successful implementation across the SC is challenging and risky. The situation is more complicated in the closed-loop supply chain (CLSC) structure. This study explores CE practices at different SC stages and the impact of their implementation on CLSC performance. This study uses a mapping tool for decision-making: SIPOC (suppliers, inputs, process, outputs, customers). We adapt and rename this tool as “circular SIPOC” based on the feed-forward and feedback flow of the complete material across different CLSC tiers. A circular SIPOC chart, coupled with institutional theory, is used to identify CE techniques from the three manufacturing CLSCs of the United Arab Emirates (UAE), supported by thematic analysis. The findings indicate two unique and standard practice classifications in SCs. They further show that traditional practices are easy to implement, while individual practices have medium to great difficulty in implementation and related SC performance. This study's contribution is the detailed list of CE-based practices in three CLSCs and the criticality of their implementation. Following the institutional theory, government institutions may use the findings of this study to put coercive, normative, and mimetic pressure on organizations, encouraging the adoption of these CE practices and helping bring the CE a step closer.

Facilitation of sensory transmission to motoneurons during cortical or sensory-evoked primary afferent depolarization (PAD) in humans.

Sensory and corticospinal tract (CST) pathways activate spinal GABAergic interneurons that have axoaxonic connections onto proprioceptive (Ia) afferents that cause long-lasting depolarizations (termed primary afferent depolarization, PAD). In rodents, sensory-evoked PAD is produced by GABAA receptors at nodes of Ranvier in Ia afferents, rather than at presynaptic terminals, and facilitates spike propagation to motoneurons by preventing branch-point failures, rather than causing presynaptic inhibition. We examined in 40 human participants whether putative activation of Ia-PAD by sensory or CST pathways can also facilitate Ia afferent activation of motoneurons via the H-reflex. H-reflexes in several leg muscles were facilitated by prior conditioning from low-threshold proprioceptive, cutaneous or CST pathways, with a similar long-lasting time course (∼200ms) to phasic PAD measured in rodent Ia afferents. Long trains of cutaneous or proprioceptive afferent conditioning produced longer-lasting facilitation of the H-reflex for up to 2min, consistent with tonic PAD in rodent Ia afferents mediated by nodal α5-GABAA receptors for similar stimulation trains. Facilitation of H-reflexes by this conditioning was likely not mediated by direct facilitation of the motoneurons because isolated stimulation of sensory or CST pathways did not alone facilitate the tonic firing rate of motor units. Furthermore, cutaneous conditioning increased the firing probability of single motor units (motoneurons) during the H-reflex without increasing their firing rate at this time, indicating that the underlying excitatory postsynaptic potential was more probable, but not larger. These results are consistent with sensory and CST pathways activating nodal GABAA receptors that reduce intermittent failure of action potentials propagating into Ia afferent branches. KEY POINTS: Controlled execution of posture and movement requires continually adjusted feedback from peripheral sensory pathways, especially those that carry proprioceptive information about body position, movement and effort. It was previously thought that the flow of proprioceptive feedback from Ia afferents was only reduced by GABAergic neurons in the spinal cord that sent axoaxonic projections to the terminal endings of sensory axons (termed GABAaxo neurons). Based on new findings in rodents, we provide complementary evidence in humans to suggest that sensory and corticospinal pathways known to activate GABAaxo neurons that project to dorsal parts of the Ia afferent also increase the flow of proprioceptive feedback to motoneurons in the spinal cord. These findings support a new role for spinal GABAaxo neurons in facilitating afferent feedback to the spinal cord during voluntary or reflexive movements.

Characterization of 2D Electrical Feedback Flow Control Valve

We proposed a novel 2D electric feedback flow control valve to solve the problem of low integration and control accuracy of flow control valves. The torque motor of the valve drives the 2D piston to rotate, and the rotational motion is converted to axial motion and drives the spool. The differential pressure feedback rod on the valve body can accurately measure the differential pressure of the oil inlet and outlet and cooperate with the spool displacement to form a closed loop of flow. This loop of flow then overcomes the influence of the valve port’s load change on the flow. We first established the mathematical model of the valve, obtained the transfer function, and performed the stability analysis. Then, we used AMESim as a platform for simulation analysis. Finally, we conducted the experimental verification of the valve. The verification showed the following characteristics of the valve. The hysteresis loop is 4.4%. The linearity is 1.6%. The response time is about 44 ms. The amplitude bandwidth is about 17 Hz. The phase bandwidth is about 28 Hz. The valve’s steady-state flow error is less than 8%, suggesting its broad application prospect in the aerospace and military fields.

Improved Gust Tolerance of a Cyclocopter UAV Using Onboard Flow Sensing

This paper describes the gust rejection study of a twin-cyclocopter micro air vehicle with two cyclorotors and an anti-torque nose rotor. A gust rejection controller relying on velocity feedback and onboard flow sensing was implemented in a closed-loop feedback system. Tethered experiments were conducted with the vehicle mounted on a 6-DOF stand in front of a synthetic gust generation device capable of providing up to 4 m/s step gust input. Planar gusts along the longitudinal and lateral axis of the cyclocopter and crosswinds were systematically studied. Both pitch control (varying nose rotor rpm) and thrust vectoring control strategies were evaluated to counteract perturbation along the longitudinal axis, while the cyclocopter used differential rotational speed of the cyclorotors for lateral gusts. Results showed that thrust vectoring was more effective than pitch control in reducing displacement from gust. Pitch control using the position feedback controller resulted in a maximum gust tolerance of 2.8 m/s with a duration of 3 s. while thrust vector control using the combined flow feedback and position feedback controller was able to withstand 4 m/s step gust input with 1 s duration with only 0.01 m displacement. In addition, flow feedback was more effective than position feedback in minimizing position error. The cyclocopter was also able to mitigate step gusts of 2.8 m/s in magnitude and 3 s duration with crosswind components at 30 deg from the longitudinal axis. The difference in performance can be attributed to the cyclocopter's unique thrust vectoring capability.

Digitalization in The Organizing of Apartment Building Major Renovation in Russia

The article substantiates the necessity and possibility of using information and communication technologies to reduce the severity and intensity of the principal-agent problem that arises in the modern system of organizing the major renovations of apartment buildings in Russia. Based on the “Arshtein ladder of civic participation” the article proposes a hierarchical model for a meaningful assessment of the existing resources of information and communication support for the major renovation system in Russia. This model includes seven levels of participation of homeowners in solving the problem of a building renovation. The analysis of the content and services of information support resources for the major renovation system of apartment buildings in Russia showed that they do not contribute to the practice of active real participation of homeowners in resolving issues of renovations, they are at the level of “symbolic” participation, providing information about the regulatory the legal framework for renovations, the structure of regulatory authorities in this area, the current activities of regional operators. The information support of the major renovation system of apartment buildings in Russia is an information flow from authorities to citizens, with a weak or absent feedback flow with the ability to control incoming initiatives and complaints, which does not allow us to state progress in mitigating the consequences of the principal-agent problem in this area.

Exploring the effect of improved learning performance: A mobile augmented reality learning system.

Students are commonly in a high cognitive load state when they encounter sophisticated knowledge. Whether the novel augmented reality (AR) technology can be utilized in an online learning course to explain complicated scientific concepts in a more understandable manner to students during the COVID-19 period is an unaddressed issue. This study aims to investigate the influences of reducing the physical touch or face-to-face teaching/learning practices via using mobile augmented reality learning systems (MARLS) on students' perceived learning effectiveness. The information feedback viewpoint, flow theory, and cognitive load theory are integrated to examine the effects of the information feedback of MARLS on students' learning effectiveness. This study recruited 204 participants from ten universities to complete a learning task via a MARLS and fill out a questionnaire to collect data for the proposed research model. The empirical results revealed information feedback positively and significantly affected flow experience, perceived learning effectiveness, and continued intention. The improved learning performance of learners was positively related to their continued intention. Also, the extraneous cognitive load negatively and significantly moderated the relationship between information feedback and perceived learning effectiveness. This study proposes meaningful implications and suggestions for future research based on the findings of this experiment.

Design of A Two-Stage Control Strategy of Vanadium Redox Flow Battery Energy Storage Systems for Grid Application

The low energy conversion efficiency of the vanadium redox flow battery (VRB) system poses a challenge to its practical applications in grid systems. The low efficiency is mainly due to the considerable overpotentials and parasitic losses in the VRB cells when supplying highly dynamic charging and discharging power for grid regulation. Apart from material and structural advancements, improvements in operating strategies are equally essential for achieving the expected high-performance VRB system, although an optimized solution has not been fully exploited in the existing studies. In this paper, a two-stage control strategy is thus developed based on a proposed and experimental validated multi-physics multi-time-scale electro-thermo-hydraulic VRB model. Specifically, in the first stage, the optimal flow rate of the VRB is obtained based on online optimization to reduce parasitic loss and enhance instantaneous system efficiency, and the result serves as the set point of a feedback flow rate controller. In the second stage, dual time scales are specifically considered. And the current and flow rate controllers are designed to meet the highly varying power demands for grid-connected applications. The effectiveness of the proposed control strategy is verified under a scenario to smooth wind power generation. Comparative studies show that compared to the prevailing approaches, higher efficiency can be achieved in tracking the theoretical optimal power profiles for online battery control.

An Exploratory Study of Music Teachers’ Flow Experiences Between Performing and Teaching Music

The purpose of this study was to examine music teachers’ experiences with flow while performing and teaching music. A model with four flow antecedents (Challenge, Skills, Goal Clarity, and Feedback) and three dimensions of flow state (Absorption, Enjoyment, and Intrinsic Motivation) was adopted to investigate music teachers’ flow experiences in performing and teaching. Two hundred twenty-five music teachers completed the Flow in Music Performing and Teaching Scale, modified from Buil et al. The analyses revealed that the four flow antecedents in the proposed model explained a substantial amount of variance in music teachers’ flow state for both performing and teaching music settings (54.0% in performing, 34.7% in teaching). Participants’ open-ended descriptions of flow were also collected to further explore music teachers’ personal experiences with flow. The open-ended descriptions revealed that music teachers cited topics pertaining to Challenge, Skills, Absorption, Enjoyment, and Flow Disruptor when describing flow in performance. In contrast, they tended to cite topics pertaining to Feedback, Goal Clarity, and Group Flow when describing flow in teaching. Because Feedback and Goal Clarity appeared to be more closely associated with flow in teaching, executing lesson plans to accomplish goals while flexibly responding to students’ spontaneous feedback may elicit flow for teaching.

Traffic flow modeling and feedback control for future Low-Altitude Air city Transport: An MFD-based approach

The imminent penetration of low-altitude passenger and delivery aircraft into the urban airspace will give rise to new urban air transport systems, which we call low-altitude air city transport (LAAT) systems. As the urban mobility revolution approaches, we must investigate (i) the collective behavior of LAAT aircraft in cities, and (ii) ways of controlling LAAT systems. Future LAAT systems exemplify a new class of modern large scale engineering systems — networked control systems. They are spatially distributed, consist of many interconnected elements with control loops through digital communication networks such that the system signals can be exchanged among all components through a common network. Therefore, a decentralized controller design in framework of the unilateral event-driven paradigm is considered. Inspired by controlled urban road networks, in this paper we first establish the concept of Macroscopic Fundamental Diagram (MFD) for LAAT systems and develop a collective and aggregate aircraft traffic flow model. Then, based on that, we design an adaptive boundary feedback flow control which is robust to various anomalies in technical devices and network communication links for LAAT systems.

Feedback and reactive flow effects on living crystal formation

Active spherical particles in a water film form aggregate on two neighboring water bubbles, where one of the bubbles’ half surface is heated by a laser source, creating a convective flow field. The specific geometry is similar to the experimental setup we used for colloidal particles (Ilday et al., 2017). Water flow is considered reactive during the simulation due to changing flow field, as well as temperature field. A feedback interaction is introduced, which may be due to the concentration of particles in some region of fluid, effectively a time-dependent accumulation. We show the effect of attractive and repulsive feedback forces, and observe, under attractive feedback, the formation of patches of aggregate distributed all over the space, and eventually a greater aggregate formation on the bubble surface. Reactive flow effects, with and without feedback effects, are analyzed, by examining the pair correlation and mean square displacement indicators, as well as the single-particle trajectories.

Mapping the Multiple Health System Responsiveness Mechanisms in One Local Health System: A Scoping Review of the Western Cape Provincial Health System of South Africa.

Background: Despite governments striving for responsive health systems and the implementation of mechanisms to foster better citizen feedback and strengthen accountability and stewardship, these mechanisms do not always function in effective, equitable, or efficient ways. There is also limited evidence that maps the diverse array of responsiveness mechanisms coherently across a particular health system, especially in low- and middle-income country (LMIC) contexts. Methods: This scoping review presents a cross-sectional ‘map’ of types of health system responsiveness mechanisms; the regulatory environment; and evidence available about these; and assesses what is known about their functionality in a particular local South African health system; the Western Cape (WC) province. Multiple forms of indexed and grey literature were synthesized to provide a contextualized understanding of current ‘formal’ responsiveness mechanisms mandated in national and provincial policies and guidelines (n = 379). Various forms of secondary analysis were applied across quantitative and qualitative data, including thematic and time-series analyses. An expert checking process was conducted, with three local field experts, as a final step to check the veracity of the analytics and conclusions made. Results: National, provincial and district policies make provision for health system responsiveness, including varied mechanisms intended to foster public feedback. However, while some are shown to be functioning and effective, there are major barriers faced by all, such as resource and capacity constraints, and a lack of clarity about roles and responsibilities. Most mechanisms exist in isolation, failing to feed into an overarching strategy for improved responsiveness. Conclusion: The lack of synergy between mechanisms or analysis of varied forms of feedback is a missed opportunity. Decision-makers are unable to see trends or gaps in the flow of feedback, check whether all voices are heard or fully understand whether/how systemic response occurs. Urgent health system work lies in the research of macro ‘whole’ systems responsiveness (levels, development, trends).

Building a Coaching Culture-The Roles of Coaches, Mentors, and Sponsors.

Building a Coaching Culture-The Roles of Coaches, Mentors, and Sponsors.

Irrational use of antibiotics in Iran from the perspective of complex adaptive systems: redefining the challenge

BackgroundIrrational use of antibiotics is proving to be a major concern to the health systems globally. This results in antibiotics resistance and increases health care costs. In Iran, despite many years of research, appreciable efforts, and policymaking to avoid irrational use of antibiotics, yet indicators show suboptimal use of antibiotics, pointing to an urgent need for adopting alternative approaches to further understand the problem and to offer new solutions. Applying the Complex Adaptive Systems (CAS) theory, to explore and research health systems and their challenges has become popular. Therefore, this study aimed to better understand the complexity of the irrational use of antibiotics in Iran and to propose potential solutions.MethodThis research utilized a CAS observatory tool to qualitatively collect and analyse data. Twenty interviews and two Focus Group discussions were conducted. The data was enriched with policy document reviews to fully understand the system. MAXQDA software was used to organize and analyze the data.ResultWe could identify several diverse and heterogeneous, yet highly interdependent agents operating at different levels in the antibiotics use system in Iran. The network structure and its adaptive emergent behavior, information flow, governing rules, feedback and values of the system, and the way they interact were identified. The findings described antibiotics use as emergent behavior that is formed by an interplay of many factors and agents over time. According to this study, insufficient and ineffective interaction and information flow regarding antibiotics between agents are among key causes of irrational antibiotics use in Iran. Results showed that effective rules to minimize irrational use of antibiotics are missing or can be easily disobeyed. The gaps and weaknesses of the system which need redesigning or modification were recognized as well.ConclusionThe study suggests re-engineering the system by implementing several system-level changes including establishing strong, timely, and effective interactions between identified stakeholders, which facilitate information flow and provision of on-time feedback, and create win-win rules in a participatory manner with stakeholders and the distributed control system.

The role of farmers and organizational networks in climate information communication: the case of Ghana

PurposeThe nature of the collaborations that exists among the organizations in the climate change and agriculture sectors can influence the tailoring of climate forecasts into information useable for adapting agricultural practices to the risks posed by climate change. Also, the extent to which farmers are integrated into this organizational collaboration network can influence their access to climate information. This paper aims to examine how organizational collaborations in the process of climate information generation and dissemination acts as either barriers or enablers of farmers’ access to and use of climate information in Ghana.Design/methodology/approachThis study used key informant interview and questionnaire survey to interview the organizations in the climate change and agriculture sectors. Using network analysis as an analytical framework, the authors estimated the networks’ core-periphery, density, reciprocity and degree centrality.FindingsThe authors observed that communication of climate information to farmers is mostly influenced by the collaborations between governmental organizations and nongovernmental organizations. Nevertheless, information flow and exchange through organizational collaboration network is having limited effect on improving farmers’ knowledge about climate risks, impacts and available risk response options. This is mostly because the feedback flow of information from farmers to national level organizations has not been effective in addressing localized climate/agro challenges.Originality/valueThis paper provides a critical overview of key issues in influencing the relevancy and usefulness of climate information in the Ghanaian agriculture sector. Insights gained and recommendations made are essential for deploying effective climate services in Ghana and can be relevant for many African countries because of similar socioeconomic contexts.