Physical Analogy Research Articles

Interdisciplinary model transfer and realism about physical analogy

Interdisciplinary model transfer and realism about physical analogy

Limb loading enhances skill transfer between augmented and physical reality tasks during limb loss rehabilitation

BackgroundVirtual and augmented reality (AR) have become popular modalities for training myoelectric prosthesis control with upper-limb amputees. While some systems have shown moderate success, it is unclear how well the complex motor skills learned in an AR simulation transfer to completing the same tasks in physical reality. Limb loading is a possible dimension of motor skill execution that is absent in current AR solutions that may help to increase skill transfer between the virtual and physical domains.MethodsWe implemented an immersive AR environment where individuals could operate a myoelectric virtual prosthesis to accomplish a variety of object relocation manipulations. Intact limb participants were separated into three groups, the load control (CGLD; N=4), the AR control (CGAR; N=4), and the experimental group (EG; N=4). Both the CGAR and EG completed a 5-session prosthesis training protocol in AR while the CGLD performed simple muscle training. The EG attempted manipulations in AR while undergoing limb loading. The CGAR attempted the same manipulations without loading. All participants performed the same manipulations in physical reality while operating a real prosthesis pre- and post-training. The main outcome measure was the change in the number of manipulations completed during the physical reality assessments (i.e. completion rate). Secondary outcomes included movement kinematics and visuomotor behavior.ResultsThe EG experienced a greater increase in completion rate post-training than both the CGAR and CGLD. This performance increase was accompanied by a shorter motor learning phase, the EG’s performance saturating in less sessions of AR training than the CGAR.ConclusionThe results demonstrated that limb loading plays an important role in transferring complex motor skills learned in virtual spaces to their physical reality analogs. While participants who did not receive limb loading were able to receive some functional benefit from AR training, participants who received the loading experienced a greater positive change in motor performance with their performance saturating in fewer training sessions.

Embodied Communication: How Robots and People Communicate Through Physical Interaction

Early research on physical human–robot interaction (pHRI) has necessarily focused on device design—the creation of compliant and sensorized hardware, such as exoskeletons, prostheses, and robot arms, that enables people to safely come in contact with robotic systems and to communicate about their collaborative intent. As hardware capabilities have become sufficient for many applications, and as computing has become more powerful, algorithms that support fluent and expressive use of pHRI systems have begun to play a prominent role in determining the systems’ usefulness. In this review, we describe a selection of representative algorithmic approaches that regulate and interpret pHRI, describing the progression from algorithms based on physical analogies, such as admittance control, to computational methods based on higher-level reasoning, which take advantage of multimodal communication channels. Existing algorithmic approaches largely enable task-specific pHRI, but they do not generalize to versatile human–robot collaboration. Throughout the review and in our discussion of next steps, we therefore argue that emergent embodied dialogue—bidirectional, multimodal communication that can be learned through continuous interaction—is one of the next frontiers of pHRI.

COMPARATIVE ANALYSIS OF THE EFFECTIVENESS OF CLINICAL DATA COLLECTION THROUGH ONLINE AND PHYSICAL ELECTRONIC QUESTIONNAIRE IN ORTHOPEDIC PATIENTS.

To compare the response rate and the accuracy of the clinical data collection date through the online and physical digital questionnaire in orthopedic patients. Comparative study, level III of evidence, with forty patients who had ankle sprains were evaluated, followed up for a period of 12 weeks with the application of physical and digital Visual Analogue Scale, Foot Function Index and Cumberland Ankle Instability Tool questionnaires, and data were collected about the moment of collection of each questionnaire. We obtained a response rate of 83.3% in the digital collection group and 60% in the physical collection group (p < 0.05), and the response rate in the digital collection group was higher at all times of collection (3, 6 and 12 weeks). Analysis of the time of collection shows greater variability in the larger physical collection group at all times of the study (2.8 vs 1.5; 4.0 vs 2.4; 8.6 vs 1.5). Digital data collection is effective for obtaining clinical data in patients with ankle sprains. Level of Evidence III, Comparative, Prospective, Longitudinal Study in Parallel Groups.

ЕХОКАМЕРА ЯК ТЕХНОЛОГІЯ КОМУНІКАЦІЙНОГО ВПЛИВУ

B a c k g r o u n d . The article examines the appearance, essence and formation of the concept of "echo chamber" in the field of philosophy. The main interpretations and practical aspects of the application of this concept by representatives of the philosophical community are considered. Considering the lack of an established version of the concept of "echo chamber", an attempt was made to define its meaning by analogy with the already established interpretation of a physical analogue, namely, a resonator. The appropriateness of such an analogy is justified. The specifics of the operation of echo chambers are considered by analogy with the operation of the resonator and its associated phenomena. The phenomenon of "intellectual inbreeding" ("geistiger Inzucht") described by H. Franke is considered. M e t h o d s . The theoretical and methodological foundations of the research are based on the principles of scientific objectivity, impartiality and systematicity. During the research, general scientific, philosophical, and special methods of studying social and political phenomena were used, including general methods of analysis, synthesis, and comparative methods. R e s u l t s . The author's understanding of the meaning of the concept of "echo chamber" and the prerequisites for its stability, which are determined by the properties of human consciousness, namely: "comfort zone", "clipping of thinking" and the principle of "own-foreign" are offered. The appropriateness of consideration and the main properties of the echo chamber as a technology of effective communication influence are substantiated. Among the methods of destroying echo chambers, the development of critical thinking skills and digital literacy, compliance with the principles of diversification of information sources and "range of reasonable alternatives", the occurrence of cognitive dissonance, as well as the phenomenon of emotional resonance are considered. C o n c l u s i o n s . Echo chambers pose a significant threat both to the harmonious development of the human personality and to the stable existence of civilized societies. Methods of countering echo chambers require further development and dissemination in society.

Development of the theory and schematic solutions of the gyroscope based on superconducting quantum interferometers

Based on the principle of equivalence of the general theory of relativity and the definition of the non-Euclidean metric of space in a non-inertial frame of reference associated with rotation, a geometric (topological) phase is found that occurs when traversing any closed loop. This approach made it possible to establish a deep physical analogy between various wave effects (both classical and quantum) in closed waveguides that arise under the conditions of their rotation. Due to the coherence of the wave function of spinless charge carriers (Cooper pairs of conduction electrons with oppositely directed spins) in superconductors in the ground quantum state (superconducting state), the appearance of a geometric phase in closed loops under rotation conditions can lead to interference effects in the presence of weak bonds in the loop. To register interference effects, it was proposed to use superconducting quantum interferometers placed in the electric field of a cylindrical or spherical capacitor. In accordance with the general theory of the geometric phase of rotation, the study obtained the basic relations between the geometric phase of rotation and the phase of the wave function induced by an external magnetic field, and an estimate of their values was obtained for acceptable values of the angular velocity of rotation, dimensions of superconducting quantum interferometers, and voltages on the capacitor. The errors in measuring the magnetic flux during the rotation of the measuring complex are determined. Taking into account the dependence of the magnitude of the geometric phase of rotation on the voltage across the capacitor and the size of the superconducting quantum interferometers, and also taking into account the specific range of angular velocities of rotation, the sensitivity of superconducting quantum interferometers to the angular velocity can be regulated by a rational choice of these parameters. Based on the results obtained, a new method for measuring magnetic fields was proposed using two superconducting quantum interferometers with different values of areas bounded by closed contours under conditions of rotational movements, which makes it possible to compensate for the disturbing influence of rotations on magnetic measurements, as well as to simultaneously determine the magnetic induction and angular velocity of rotation.

Utilization mechanism of foam flooding and distribution situation of residual oil in fractured-vuggy carbonate reservoirs

The development of fractured-vuggy carbonate reservoirs is extremely difficult because of the complex fractured-vuggy structure and strong heterogeneity. Foam flooding is a potential enhanced oil recovery (EOR) technology in fractured-vuggy carbonate reservoirs. Based on the similarity criterion, three types of 2D visual physical models of the fractured-vuggy structure were made by laser ablation technique, and a 3D visual physical model of the fractured-vuggy reservoir was made by 3D printing technology. Then the physical analog experiments of foam flooding were carried out in these models. The experimental results show that foam can effectively improve the mobility ratio, control the flow velocity of the fluid in different directions, and sweep complex fracture networks. The effect of foam flooding in fractures can be improved by increasing foam strength and enhancing foam stability. The effect of foam flooding in vugs can be improved by reducing the density of the foam and the interfacial tension between foam and oil. Three types of microscopic residual oil and three types of macroscopic residual oil can be displaced by foam flooding. This study verifies the EOR of foam flooding in the fractured-vuggy reservoir and provides theoretical support for the application of foam flooding in fractured-vuggy reservoirs.

A reinforcement-based mechanism for discontinuous learning

Problem-solving and reasoning involve mental exploration and navigation in sparse relational spaces. A physical analogue is spatial navigation in structured environments such as a network of burrows. Recent experiments with mice navigating a labyrinth show a sharp discontinuity during learning, corresponding to a distinct moment of "sudden insight" when mice figure out long, direct paths to the goal. This discontinuity is seemingly at odds with reinforcement learning (RL), which involves a gradual build-up of a value signal during learning. Here, we show that biologically plausible RL rules combined with persistent exploration generically exhibit discontinuous learning. In tree-like structured environments, positive feedback from learning on behavior generates a "reinforcement wave" with a steep profile. The discontinuity occurs when the wave reaches the starting point. By examining the nonlinear dynamics of reinforcement propagation, we establish a quantitative relationship between the learning rule, the agent's exploration biases, and learning speed. Predictions explain existing data and motivate specific experiments to isolate the phenomenon. Additionally, we characterize the exact learning dynamics of various RL rules for a complex sequential task.

A Comparison between the Post-Operative Pain Relief in Total Hystrectomy with Epidural Bupivacaine and TAP Block

Background: Anesthesia is essential in the treatment of postoperative pain. Epidural analgesia and trans versus abdominis plane (TAP) block are possible options for analgesia for abdominal surgery. Objective: The main objective of the study is to evaluate and compare the efficacy of epidural bupivacaine and trans versus abdominus plane (TAP) block to provide better post-operative pain relief in total abdominal hysterectomy. Study design and place of study: This study was a prospective randomized control trial conducted at Department of anesthesiology, Liaquat National Hospital, Karachi for the period July 2017- July, 2018. Methods: Total 101 patients were enrolled thorough pre anesthetic assessment before surgery and an informed and written consent was obtained. Patients were allocated in group A and B after taking all ASA monitoring, participants in group A had an epidural catheter passed while Group B patients were given transversus abdominis plane block intra-operatively. A Visual Analogue Scale (VAS) score was used to assess anxiety levels. Statistical test like the chi-square test was used, with a p-value of 0.05 being considered statistically significant Results: Total 101 participants enrolled, the average age was 45.48 ± 1.06 (Age Rang 30-60years). The mean age of patient in Epidural Group was 47.02± 7.62 as ccompared with TAP Block Group was 43.56± 13.35 with p-value 0.007. Majority of the patients has ASA II, 39(61.9%) and 24(38.1%) respectively with p-value 0.240. Pain score at 10 minutes in epidural and TAP Block was reported as 2.16±2.1o and 3.0±2.94 (mild pain) with p-value 0.000 while after 6 hours, the VAS pain score showed mild pain in epidural group as 1.96±1.67 but moderate to severe pain was observed in TAP block patients as 4.28±1.56 with insignificant p-value 0.162. Study findings will help care taker staff for Post-Operative Pain Relief after the surgery , the benefits of single shot TAP block could be of advantage in situations where epidural analgesia is contraindicated or not desired. Conclusion: The study concluded better pain relief in patients with epidural bupivacaine when compared with TAP block. Keywords: TAP Transversus Abdominus Plane ASA Physical Status Score VAS Visual Analogue Scale Epidural block, postoperative pain relief, Total Abdominal Hysterectomy, Transversus Abdominis Plane Block

The Effects of Noninvasive Vagus Nerve Stimulation on Fatigue in Participants With Primary Sjögren’s Syndrome

ObjectivesFatigue is one of the most important symptoms needing improvement in Primary Sjögren's syndrome (PSS). Previous data from our group suggest that noninvasive stimulation of the vagus nerve (nVNS) may improve symptoms of fatigue. This experimental medicine study uses the gammaCore device (electroCore) and a sham device to investigate the relationship between nVNS and fatigue in PSS, and to explore potential mechanisms involved. Materials and MethodsForty participants with PSS were randomly assigned to use active (n = 20) or sham (n = 20) nVNS devices twice daily for 54 days in a double-blind manner. Patient-reported measures of fatigue were collected at baseline and day 56: Profile of Fatigue (PRO-F)-Physical, PRO-F-Mental and Visual Analogue Scale of abnormal fatigue (fVAS). Neurocognitive tests, immunologic responses, electroencephalography alpha reactivity, muscle acidosis, and heart rate variability were compared between devices from baseline to day 56 using analysis of covariance. ResultsPRO-F-Physical, PRO-F-Mental, and fVAS scores were significantly reduced at day 56 in the active group only (p = 0.02, 0.02, and 0.04, respectively). Muscle bioenergetics and heart rate variability showed no change between arms. There were significant improvements in digit span and a neurocognitive test (p = 0.03), and upon acute nVNS stimulation, frontal region alpha reactivity showed a significant negative relationship with fatigue scores in the active group (p < 0.01). ConclusionsWe observed significant improvements in three measures of fatigue at day 56 with the active device but not the sham device. Directly after device use, fatigue levels correlate with measures of alpha reactivity, suggesting modulation of cholinergic system integrity as a mechanism of action for nVNS.

Dynamic response of multi-scale geophysical systems: waves and practical applications.

In this review paper, we discuss the nature of an apparent link between heterogeneities associated with geological anomalies hidden from direct observation, detected when they are analysed remotely from various distances-including borehole conditions as well as aero imaging. Here, the main emphasis is placed on geological and geophysical features represented by spatially distributed signals measured along drilled well or along predefined spatial routes. In the common practice of indirect measurements of parameters of seismically active regions, there exist certain observations on correlations in the vicinity of structural and geological anomalies, repeated patterns in the representation of correlation functions and corresponding classification in multidimensional statistical methods. Underlying natural physical processes, which determine the structure of the primary anomalous environment, are of interest. Physical analogies, based on the mathematical modelling and generalization of empirical data, may suggest that such a process may be linked to wave phenomena on a geological scale. Applications include analysis of anomalies associated with non-potential fields, mapping of geodynamic zones and seismic microzoning; reconstruction of the geostructural vertical section of the mountainous regions. This article is part of the theme issue 'Wave generation and transmission in multi-scale complex media and structured metamaterials (part 2)'.

Engagement with social media content results in lower appearance satisfaction: An experience sampling study using a wrist-worn wearable and a physical analogue scale

Social media use is consistently associated with more negative body image, but much of this literature is cross-sectional and/or lacks ecological validity. To overcome these limitations, we examined associations between everyday social media engagement and appearance satisfaction using an experience sampling method. Fifty participants from Central Europe completed a 14-day experience sampling phase in which they reported their appearance satisfaction at two random time-points each day, as well as following active engagement with social media content, using a wrist-worn wearable and a physical analogue scale (PAS; i.e., angle of a participant’s forearm between flat and fully upright as a continuous response scale). Results indicated that engagement with social media content was significantly associated with lower appearance satisfaction. Additionally, we found that engagement with the content of known others was associated with significantly lower appearance satisfaction than engagement with the content of unknown others. These effects were stable even after controlling for participant demographics, active vs. passive daily social media use, and body image-related factors. These results provide evidence that everyday social media engagement is associated with lower appearance satisfaction and additionally provides preliminary support for the use of a PAS in body image research using an experience sampling method.

Simulating hydrologic pathway contributions in fluvial and karst settings: An evaluation of conceptual, physically-based, and deep learning modeling approaches

Hydrologic models are robust tools for estimating key parameters in the management of water resources, including water inputs, storage, and pathway fluxes. The selection of process-based versus data-driven modeling structure is an important consideration, particularly as advancements in machine learning yield potential for improved model performance but at the cost of lacking physical analogues. Despite recent advancement, there exists an absence of cross-model comparison of the tradeoffs between process-based and data-driven model types in settings with varying hydrologic controls. In this study, we use physically-based (SWAT), conceptually-based (LUMP), and deep-learning (LSTM) models to simulate hydrologic pathway contributions for a fluvial watershed and a karst basin over a twenty-year period. We find that, while all models are satisfactory, the LSTM model outperformed both the SWAT and LUMP models in simulating total discharge and that the improved performance was more evident in the groundwater-dominated karst system than the surface-dominated fluvial stream. Further, the LSTM model was able to achieve this improved performance with only 10–25% of the observed time-series as training data. Regarding pathways, the LSTM model coupled with a recursive digital filter was able to successfully match the magnitude of process-based estimates of quick, intermediate, and slow flow contributions for both basins (ρ ranging from 0.58 to 0.71). However, the process-based models exhibited more realistic time-fractal scaling of hydrologic flow pathways compared to the LSTM model which, depending on project objectives, presents a potential drawback to the use of machine learning models for some hydrologic applications. This study demonstrates the utility and potential extraction of physical-analogues of LSTM modeling, which will be useful as deep learning approaches to hydrologic modeling become more prominent and modelers look for ways to infer physical information from data-driven predictions.

Teaching Groundwater Flow and Contaminant Transport Modeling via a Sand-Tank Model

In this study, a sand-tank model as a physical analog of a real-world aquifer is presented for groundwater instruction. The sand tank is used for introducing flow nets and quantifying groundwater flow, for groundwater modeling and calibration via a spreadsheet, and for dye-transport modeling. Students learn from the sand tank through interaction and visualization, and by collecting and interpreting data. This integrates the theories from lectures into the sand-tank laboratories, enhancing students’ skills and understanding.

Transverse spin and the hidden vorticity of propagating light fields.

Spatially inhomogeneous fields of electromagnetic guided modes exhibit a complex of extraordinary dynamical properties such as polarization-dependent transverse momentum, helicity-independent transverse spin, spin-associated non-reciprocity and unidirectional propagation, etc. Recently, the remarkable relationship has been established between the spin and propagation features of such fields, expressed through the spin-momentum equations [Proc. Natl. Acad. Sci. USA118, e2018816118 (2021) PNASA60027-842410.1073/pnas.2018816118] connecting the wave spin with the curl of momentum. Here, the meaning, limitations, and specific forms of this correspondence are further investigated, involving physically transparent and consistent examples of paraxial light fields, plane-wave superpositions, and evanescent waves. The conclusion is inferred that the spin-momentum equation is an attribute of guided waves with a well-defined direction of propagation, and it unites the helicity-independent "extraordinary" transverse spin with the spatially inhomogeneous longitudinal field momentum (energy flow) density. Physical analogies with the layered hydrodynamic flows and possible generalizations for other wave fields are discussed. The results can be useful in optical trapping, manipulation, and data processing techniques.

Type-2 Fuzzy Sets and Newton’s Fuzzy Potential in an Algorithm of Classification Objects of a Conceptual Space

This paper deals with Gärdenfors’ theory of conceptual spaces. Let {mathcal {S}} be a conceptual space consisting of 2-type fuzzy sets equipped with several kinds of metrics. Let a finite set of prototypes tilde{P}_1,ldots ,tilde{P}_nin mathcal {S} be given. Our main result is the construction of a classification algorithm. That is, given an element {tilde{A}}in mathcal {S}, our algorithm classifies it into the conceptual field determined by one of the given prototypes tilde{P}_i. The construction of our algorithm uses some physical analogies and the Newton potential plays a significant role here. Importantly, the resulting conceptual fields are not convex in the Euclidean sense, which we believe is a reasonable departure from the assumptions of Gardenfors’ original definition of the conceptual space. A partitioning algorithm of the space mathcal {S} is also considered in the paper. In the application section, we test our classification algorithm on real data and obtain very satisfactory results. Moreover, the example we consider is another argument against requiring convexity of conceptual fields.

Performance of a submerged piezoelectric wave energy converter device floating over an undulated seabed

In this study, the power absorption of a submerged piezoelectric wave energy converter (PWEC) device floating over a rippled seabed is investigated under the linear water wave theory. The boundary element method (BEM) is used to solve the physical problem analogs to the hydrodynamics of the PWEC device. The effect of different structural parameters such as the length of the piezoelectric plate, submergence depth, amplitude, and the number of ripples of the sinusoidal seabed on the power generation of the PWEC device is examined. The study demonstrates that the PWEC plate having moderate length can produce the highest power in the shortwave regime. Further, positioning the PWEC near the free surface can generate more power from ocean wave energy.

Branching structure of genealogies in spatially growing populations and its implications for population genetics inference

Spatial models where growth is limited to the population edge have been instrumental to understanding the population dynamics and the clone size distribution in growing cellular populations, such as microbial colonies and avascular tumours. A complete characterization of the coalescence process generated by spatial growth is still lacking, limiting our ability to apply classic population genetics inference to spatially growing populations. Here, we start filling this gap by investigating the statistical properties of the cell lineages generated by the two dimensional Eden model, leveraging their physical analogy with directed polymers. Our analysis provides quantitative estimates for population measurements that can easily be assessed via sequencing, such as the average number of segregating sites and the clone size distribution of a subsample of the population. Our results not only reveal remarkable features of the genealogies generated during growth, but also highlight new properties that can be misinterpreted as signs of selection if non-spatial models are inappropriately applied.

Continuous Extraction and Continuous Backfill Mining Method Using Carbon Dioxide Mineralized Filling Body to Preserve Shallow Water in Northwest China

The exploitation and utilization of coal resources are not only prone to causing water table lowering, but also produce a large amount of CO2 and coal-based solid waste. A scientific concept that employs the CO2 and solid wastes to develop filling bodies and inject them into the mined-out area, to sequestrate CO2 and mitigate the overburden migration and thus preserve the overlying aquifer, is proposed. Continuous extraction and continuous backfill (CECB) mining was selected as the mining method to meet the aforementioned objectives. Additionally, carbon dioxide mineralized filling body (CMFB) under ambient temperature and pressure was developed, with fly ash as aggregate, and CO2 gas, silicate additives and cement as accessories. The uniaxial compressive strength (UCS) and tensile strength of CMFB with various curing times and fly ash contents were tested indoors. A physical analogue simulation and FLAC3D numerical calculation were then successively implemented on the premise of determining a similar material ratio of CMFB in analogue simulation and calibrating the parameters of the CMFB in numerical simulation. The deformation of aquifuge and water level lowering while using CECB and CMFB with various proportion of fly ash were obtained. When using the CMFB with 75% fly ash content and 28 d curing time, the maximum values of vertical displacement, horizontal displacement, inclination, horizontal deformation and curvature of aquiclude were 26 mm, 6.5 mm, 0.12 mm/m, 0.08 mm/m and 0.0015 mm/m2, respectively, and the water table decreased 0.47 m. The results show that the CMFB with 75% fly ash is the most appropriate ratio to realize water preservation mining, CO2 sequestration and harmless treatment of solid wastes, contributing to the green and sustainable development of coal areas.

A fast, heuristic method for generating offshore wind farm turbine layouts

This paper describes a heuristic method for generating turbine layouts for offshore wind farms, applying a physical analogy between particle motion in a potential field and turbine placement in a wind kinetic energy field. The method is fast, and relies on industry-standard wake models to account for internal and external wake. The method is heuristic in several senses; it is based on physical analogy, it does not solve the wake model explicitly during the iterative process, and it does not necessarily provide an optimal solution at the end of iteration. The current method does not aim to outperform a full optimization with an objective function, explicit wake model solution and an heuristic optimizer algorithm, but the computational speed and simplicity makes it well suited for screening purposes and as initial solutions for more time-consuming methods.