Fidelity Simulation Research Articles

Analysis of human performance differences between students and operators when using the Rancor Microworld simulator

From within the umbrella of the Simplified Human Error Experimental Program (SHEEP) framework, this paper analyzes human performance differences between professional and student operators when using a simplified simulator (i.e., Rancor Microworld). This paper represents a crucial step in understanding the fidelity of the simplified simulators and student operators within the SHEEP study. This paper explores a randomized factorial experimental design that features two independent variables: participant type and event class. Six human performance measurements are considered in the experiment. The experiment is conducted using 20 professional reactor operators employed at actual nuclear power plants (NPPs), along with 20 trained students. The experimental data are analyzed via statistical analysis methods. Lastly, this paper examines the differences in human performance between actual operators and students when using Rancor Microworld.

A High-Fidelity Simulation Platform for Industrial Manufacturing by Incorporating Robotic Dynamics Into an Industrial Simulation Tool

Simulation provides an efficient and safe evaluation solution for industrial automation to pretest software before deploying it in real systems. However, only high-fidelity simulation environments that precisely reconstruct the behavioral patterns of real systems can guarantee a successful transfer from simulation to reality (sim-to-real). Many existing industrial simulation tools provide libraries for various industrial devices, which simplify the development efforts significantly, but they generally lack the ability to model the system dynamics and often fail to generate a realistic representation when the system performance is sensitive to the modeling deviation. For example, robots equipped with intelligent algorithms potentially lead to task failure if the software is sensitive to the variation of the system dynamics. In this paper, we design a novel simulation platform for industrial manufacturing use cases consisting of a cooperative robot and a modular manufacturing device. With the dynamic model of the robot integrated into a manufacturing digital-twining software, the platform achieves high simulation fidelity by incorporating the effect of the robot dynamics to the control logic of the industrial tasks. Also, the simulation can exchange data with the real robot via an open protocol, which enables the simultaneous test of the real and simulated systems. Two experiments are conducted on the simulation platform to validate its fidelity in terms of the consistent control logic with the real system. Also, a workpiece distribution use case is studied to show how the simulation platform is used to develop a task-planning algorithm for a manufacturing application.

Uniaxial model for simulating the cyclic behavior of reinforced concrete members

AbstractA new computational model is proposed within the lumped‐plasticity framework to simulate the lateral load‐deformation response of reinforced concrete members up to complete loss of lateral strength. The proposed model implements new features that enhance simulation fidelity of reinforced concrete members. It employs a cubic spline function to simulate the gradual changes of stiffness observed in the unloading‐reloading behavior of concrete members under seismic loading. The proposed model takes a different approach to simulating cyclic behavior from existing models, by utilizing an energy dissipation term as the central parameter to adjust the level of pinching in a response. The model replicates the amount of cyclic energy dissipation specified by the user, regardless of other parameters. It also automatically adjusts cyclic energy dissipation with increasing lateral deformations, to match experimental observations from concrete members. The model is equipped with deformation and energy‐based damage functions that can realistically capture stiffness and strength damage in concrete members, even under non‐symmetric cyclic loading. Using these functionalities, the model can adjust the lateral load‐deformation backbone response based on load‐history to account for short‐ or long‐duration non‐symmetric ground motion inputs. The proposed model is applicable for simulating the lateral shear or moment behaviors of reinforced concrete members, such as columns, beams, walls, and joints. The model is implemented in the open‐source simulation platform OpenSees as the CyclicReinforcedConcrete model.

IMPULSED model based cytological feature estimation with U-Net: Application to human brain tumor at 3T.

This work introduces and validates a deep-learning-based fitting method, which can rapidly provide accurate and robust estimation of cytological features of brain tumor based on the IMPULSED (imaging microstructural parameters using limited spectrally edited diffusion) model fitting with diffusion-weighted MRI data. The U-Net was applied to rapidly quantify extracellular diffusion coefficient (Dex ), cell size (d), and intracellular volume fraction (vin ) of brain tumor. At the training stage, the image-based training data, synthesized by randomizing quantifiable microstructural parameters within specific ranges, was used to train U-Net. At the test stage, the pre-trained U-Net was applied to estimate the microstructural parameters from simulated data and the in vivo data acquired on patients at 3T. The U-Net was compared with conventional non-linear least-squares (NLLS) fitting in simulations in terms of estimation accuracy and precision. Our results confirm that the proposed method yields better fidelity in simulations and is more robust to noise than the NLLS fitting. For in vivo data, the U-Net yields obvious quality improvement in parameter maps, and the estimations of all parameters are in good agreement with the NLLS fitting. Moreover, our method is several orders of magnitude faster than the NLLS fitting (from about 5min to <1s). The image-based training scheme proposed herein helps to improve the quality of the estimated parameters. Our deep-learning-based fitting method can estimate the cell microstructural parameters fast and accurately.

Simulation Fidelity in the Context of Surgical Training in Orthopaedics

Simulation Fidelity in the Context of Surgical Training in Orthopaedics

Interrater Reliability of the Simulation Fidelity (SiFi) Scale

A limitation of the extant research on the training effectiveness of high versus low fidelity simulation is the lack of a standardized methodology to define high and low fidelity in way that is generalizable across studies. This paper presents a novel approach to standardizing the definition of fidelity using The Simulation Fidelity (SiFi) scale. The SiFi scale is a 6-point scale used to rate the fidelity of a simulation. The present study examines the inter-rater reliability of the SiFi scale to define the fidelity of simulated task elements with respect to their real-world referent. Two subject matter experts (SMEs) completed a series of aviation maneuvers in a virtual reality (VR) simulator. Following the maneuvers, each SME provided 117 ratings of simulated elements using the SiFi scale. Cohen’s k was calculated to determine interrater reliability. Results of this analysis indicate strong reliability of the SiFi scale.

Virtual Reality Simulation for Emergency Management teams – A Literature Review

The objective of this review was to provide a summary of virtual reality (VR) simulation for emergency management (EM) teams and suggest future research agenda items. A systematic literature review was conducted using three databases: PsycINFO, Compendex (Engineering Village), and Web of Science. A total of five articles met inclusion criteria and thus were reviewed here. Our review identified four common aspects of VR-based EM team simulation: coordination, communication, decision-making, and situation awareness. Future research is recommended to investigate other aspects of team cognition and collective characteristics as to how these are related to team performance. The level of fidelity of the VR simulation was identified as an important factor to consider when designing VR simulations for different populations with varying experience level. The adoption of more immersive VR systems would be beneficial to improving ecological validity. Moreover, a deep analysis of fidelity and simulation effectiveness is recommended.

Machine learning for predicting microfluidic droplet generation properties

Computational Fluid Dynamics (CFD) simulators are an integral tool for designing commercial microfluidic systems — allowing engineers to estimate key performance metrics prior to physical prototyping. However, CFD simulations can take from hours to weeks, depending on the simulation fidelity. This introduces a significant delay in the design iteration loop. In this work, we employ machine learning methodologies to provide estimates of performance metrics directly from microfluidic geometries in inkjet printheads — providing approximate performance metrics in seconds. Specifically, we develop a Convolutional Neural Network (CNN) based approach that operates directly on voxelized slices of printhead geometry to predict characteristics of droplet generation. This approach does not encode significant biases for the task or physics knowledge and relies on a training set of 20,000 prior simulation results to learn. Despite this, our experiments on this large dataset demonstrate that the learned model can closely approximate the CFD results at a fraction of the time cost for some performance metrics — opening the doors to real-time metric estimation as part of the microfluidic system design process. Further, we examine the learned latent representation and find it encodes a reasonable notion of geometric similarity between printhead architectures. This can allow engineers to search for existing designs with similar characteristics and help reduce duplicated effort.

Redesign Driven by Manufacturing Data for Next-Generation Modernization of Legacy Products

Abstract As the life cycles of many products advance, obsolescence of original components can pose challenges for a product’s maintainability and serviceability. Information about the original design intent of the product system may not be available. For example, it may not be obvious how to identify old components by reverse engineering or to select and configure the optimal components for best system performance. Thus, time spent to redesign an older legacy product with high-fidelity simulations may be difficult to justify. Increasingly more performance measurements are available in digital twins of product systems generated during manufacturing and testing. This paper introduces a redesign from manufacturing data mapping (RfMDM) method that can infer optimal new components to modernize legacy product systems. This RfMDM method does not rely upon time-consuming redesign efforts. The inputs come from a basic understanding of the subsystem of concern and qualitative scoring estimates of the influence of design rules on design criteria and simulation fidelity. RfMDM transforms manufacturing data to determine the significance and required quality of each design variable of each obsolete component. This enables estimation of optimal new component specifications for selection and a first article redesign and test to enable product line improvements over time more efficiently. Recognizing that radiofrequency interference effects in printed circuit boards present a complex and quintessential example of legacy subsystems with potentially obsolete components, this paper demonstrates the RfMDM method with a theoretical example subsystem of an active low-pass filter on a printed circuit board.

Physiologic Fidelity as a Domain in Assessing Mixed Reality Trauma Simulation.

Mixed reality has been used in trauma and emergency medicine simulation for more than a decade. As mixed reality potential in trauma simulation continues to expand, so too does the need to validate it as a surrogate for real-life emergency scenarios. Validation of these simulations can occur by measuring fidelity, or the degree to which a computing system can reproduce real-world experiences. After performing a literature review, we determined that most fidelity assessments of trauma and emergency simulations focus on how the user subjectively experiences the simulation. Although subjective user assessment is an important component of determining fidelity, we pose an introductory three-part framework that may assess mixed reality trauma simulation more adequately. A literature review was conducted using Google Scholar, PubMed, and the Uniformed Services University PowerER search database. Relevant articles were assessed to identify how studies measured fidelity in trauma simulation. We then designed the three-part framework to aid researchers in assessing the fidelity of mixed reality trauma simulations. The domains we determined to best assess mixed reality emergency simulation are as follows:1. Continue assessing fidelity via subjective user assessments. This allows the researcher to know how real the simulation looked and felt to the user based on their individual report.2. Determine whether the trauma simulation changes the medical decision-making capacity of the user. If the user's decision-making capacity changes with a stress-inducing trauma simulation versus a non-stress-inducing simulation, then the stress-inducing trauma environment would be approaching greater fidelity.3. Study the domain of our newly proposed concept: physiologic fidelity. We define physiologic fidelity as the degree to which the simulation elicits a measurable, autonomic response independent of observed emotion or perceived affect. Recreating objective autonomic arousal may be the best way to ensure a trauma simulation reaches fidelity. We propose a methodology to assess mixed reality trauma simulation fidelity. Once fidelity is more fully known to the researcher and the simulation user, adjustments can be made to approach reality more closely. Improved simulators may enrich the preparedness of both junior and senior learners for real-life emergencies. We believe assessing the three domains using the Wide Area Virtual Experience at the Val G. Hemming simulation center in Bethesda, MD, will validate mixed reality-trauma simulators as invaluable surrogates for real-life emergency scenarios and ultimately contribute to improved clinical outcomes for clinicians and their patients.

Evaluating Medic Performance in Combat Casualty Care Simulation and Training: A Scoping Review of Prospective Research.

Combat medics are required to perform highly technical medical procedures in austere environments with minimal error. Effective means to quantify medic performance in field and simulated environments are critical to optimize medic training procedures as well as to evaluate the influence of medical equipment and other supportive technologies on medic performance. Human performance evaluation in combat casualty care presents many unique challenges due to the unique environment (battlefields) and population (medics) that must be represented. Recent advances in simulation and measurement technology have presented opportunities to improve simulation fidelity and measurement quality; however, it is currently unclear to what extent these advances have been adopted in this domain. In this work, a scoping review of recent (2011-2021) prospective research on Army medic (68 W and Special Operations) performance is presented. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines served as the framework for the review. The goal of this work was to summarize recent trends and practices and to illuminate opportunities for future work. Two human factors experts performed an exhaustive review of relevant, peer-reviewed literature and systematically identified articles for inclusion in the final analysis. The articles were examined in detail, and data elements of interest were extracted. Forty-eight articles were identified based on the defined inclusion criteria. Thirty three of the articles focused on technological evaluation, 25 focused on medic training procedures, and 5 focused on evaluating medical techniques. Study contributions were predominantly related to medic training materials/procedures and simulator technology. Supportive medical technologies, including telemedical systems, hemorrhage control devices, and ultrasound devices, also received significant attention. Timing was the most common metric used to quantify medic performance, followed by skill pass/fail ratings. There was a notable lack of neurophysiological data used to examine medic physical/cognitive workload during procedures, a growing practice in many other related domains. The most commonly simulated procedures were hemorrhage control, airway management, and thoracostomy. Notable limitations cited across articles were insufficient simulation fidelity, inadequate sample size or sample representativeness, and poor study design. This work provided a summary of recent peer-reviewed research related to medic simulation and training, and performance evaluation. This article should be used to contextualize existing research and inspire new research questions. Expanding and advancing research on medic simulation and training will help to ensure optimal casualty care at the front lines.

Evaluation of teaching effect of first-aid comprehensive simulation-based education in clinical medical students.

BackgroundAlthough students mastered the composition skills, they lack of the ability to effectively integrate these composition skills in real clinical situations. To address the problem, we set up different levels of situational simulation training for medical students in grades 2–4, and evaluate the teaching effect of first-aid situation comprehensive simulation-based education (SBE) on clinical medical students.MethodsThe medical students in Grade 2, 3, and 4 received different situational SBE, respectively. The 2nd-year medical students received a single skill module which included cardiopulmonary resuscitation, endotracheal intubation, and electric defibrillation training. The 3rd-year medical students received a single subject module which included cardiovascular and respiratory system training. The 4th-year medical students received the integrated multidisciplinary module which combined first-aid skills, clinical thinking, and teamwork training. The primary outcome was the expert evaluation and peer evaluation. The secondary outcome was students' satisfaction questionnaire response. In our training, we arranged an adequate teaching staff for intensive training and timely feedback (the student–teacher ratio of 5:1), adequate time for repetitive practice (Each SBE was carried out within 4 h), curriculum design, and integration from real cases by clinicians, realistic computer-driven mannequins to ensure simulation fidelity, providing a different difficult level of SBE to different grades of students, and pre- and post-tests for outcome measurement.ResultsIn all of the single skill module, single subject module or comprehensive disciplines module, the scores in the expert evaluation and peer assessment after the training were significantly higher than before the training, and the differences were statistically significant (p < 0.05). The integrated subject training, although having the lowest pre—and post-test marks, had the largest increase in score.ConclusionThe first aid comprehensive simulation-based education in grade 2–4 clinical medical students, basing on timely feedback, repetitive practice, curriculum integration, simulation fidelity, and outcome measurement are effective in improving the students' proficiency in managing the real emergencies.

Western Pacific Premoistening for Eastward-Propagating BSISO and Its ENSO Modulation

Abstract The boreal summer intraseasonal oscillation (BSISO) is a major source of subseasonal predictability of the East Asian summer monsoon. However, modeling and prediction of the BSISO remain major challenges partly due to an incomplete understanding of its eastward propagation. Our moisture budget analysis suggests that western Pacific (WPAC) premoistening leading the eastward-propagating (EP) BSISO is mainly attributed to the horizontal moisture advection with two centers in the lower and middle troposphere, respectively. The lower-tropospheric center is rooted in the linear moisture advection by flows from both the mean state and BSISO, while the middle-tropospheric center is induced by the nonlinear eddy moistening effect from the suppressed activity of synoptic tropical depression (TD) disturbances. The vertical profile of WPAC premoistening is significantly modulated by El Niño–Southern Oscillation (ENSO), with the premoistening being enhanced in the lower troposphere and weakened in the middle troposphere during an El Niño summer, and vice versa in a La Niña summer. During an El Niño summer, the nonlinear eddy moistening effect is weakened in the middle troposphere due to less southwest–northeast tilt of the TD, while the linear moisture advection is enhanced in the lower troposphere due to strengthened background cross-equatorial flows and moisture gradients. These results suggest an urgent need to improve the simulation fidelity of the BSISO’s scale interactions with synoptic and interannual variabilities in climate models. Significance Statement In this work, we use statistical analysis to explore multiscale interactions of BSISO with synoptic and interannual variabilities using observations and reanalysis data. Our key finding shows that the ENSO significantly modulates the premoistening process of the BSISO over the WPAC. In an El Niño summer, the WPAC nonlinear eddy moistening effect leading the BSISO is weakened in the midtroposphere due to smaller southwest–northeast tilt of the TD, while the linear moistening effect is enhanced in the lower troposphere due to enhanced background cross-equatorial flow and moisture gradient. These results offer new metrics for validating climate models and for projecting BSISO’s future change under different global warming scenarios.

Evaluating Usability and User Experience of AR Applications in VR Simulation

Validating an augmented reality application in a virtual reality simulation can offer many advantages compared to testing in real conditions and can speed up development processes. With such a simulation, developers and designers do not need to have constant physical access to the real place. They can save physical navigation, experiment with different kinds of devices and isolate testing parameters. While the validity of functional testing in virtual reality simulations is not particularly challenged, the validity of such simulations to evaluate user experience and usability, similarly as in real conditions, still needs to be assessed. We then conducted a user study to explore the validity of evaluating these criteria with a virtual reality simulation tool and the importance of simulation fidelity for that purpose. Indeed, we also seek to determine whether it is necessary to simulate the limited field of view of augmented reality glasses and if the simulation can take place in a virtual world that is not a replica of the real targeted environment. To do so, we have developed an augmented reality application for smart-homes where a user can interact with different connected objects. One group of users performed the experiment in the real place with augmented reality glasses and three other groups performed the same experiment in virtual reality with various simulation conditions (field of view and environment). Users’ subjective feedback and quantitative results only highlight very few differences between real-world conditions and simulation in virtual reality, whatever the simulation parameters used. These results suggest the interest in using virtual reality simulation to evaluate an augmented reality application but should be confirmed on other use cases and interaction tasks.

Towards real time transient mGT performance assessment: effective prediction using accurate component modelling techniques

In an energy mix driven by renewables, there is a need for small-scale highly efficient and flexible cogeneration units, such as Micro Gas Turbines (mGTs). These mGTs should perform transient operations and work at part-load to meet the power grid requirements. Therefore, full transient characterisation is necessary. One of the most crucial factors is accurately incorporating each component's dynamic behavior. Compressor and Turbine performance maps, although essential, are usually obtained in costly test rigs or CFD simulations. Also, the accurate modelling of the heat exchanger affects the efficiency of the whole cycle. The aim of this work is the development of real time transient mGT model, where we focus in the first step on accurate component modelling. Hence, an effective performance map representation method for mGT's compressor and turbine was developed. Moreover, a Recuperator 1-D numerical model is developed. Those modelling techniques were tested in a MATLAB/SIMULINK model in transient conditions. The fundamental target of this study is to enhance the fidelity of dynamic simulations for small-scale gas turbines. Key parameters like shaft speed and combustor inlet temperature, show deviation from experiments less than 1% which solidifies our aim to establish a general and efficient performance prediction.

Physics of gust response mitigation in open-loop pitching manoeuvres

This paper experimentally investigates the flow field development and unsteady loading of three force-mitigating pitch manoeuvres during a transverse gust encounter. The manoeuvres are constructed using varying levels of theoretical and simulation fidelity and implemented as open-loop kinematics in a water towing tank. It is found that pitch actuation during a gust encounter results in two important changes in flow topology: (i) early detachment of the leading-edge vortex (LEV) and (ii) formation of an LEV on the pressure side of the wing upon gust exit. Each of the pitch manoeuvres is found to mitigate a significant portion of the circulatory contribution of the lift force while only manoeuvres with accurate modelling of the added-mass force are found to adequately mitigate the total lift force. The penalty of aerodynamic lift mitigation using pitch manoeuvres was a twofold increase in the pitching moment transients experienced by the wing for all cases. By quantifying changes in the vertical gust momentum before and after the encounter, lift-mitigating manoeuvres were found to reduce the disturbance to the gust's flow field, thereby reducing the momentum exchange between the gust and the wing.

High Fidelity Simulation of Hybrid Systems using Higher Order Hybrid Automata

Hybrid systems are a subset of Cyber-Physical System (CPS), where a physical process (the plant) is controlled by a discrete controller. The controller induces mode switches, which are modelled as guard conditions leading to sudden discontinuities. Correctly capturing sudden discontinuities during simulation is the primary challenge to maintain fidelity. De-facto industry standard tools, such as Simulink and Modelica, have been known to produce incorrect outputs when simulating systems involving complicated guards. For example, transcendental guards leading to the well-known even number of level crossing detection problem or guards leading the system state into the complex plane have been shown to produce invalid results. To tackle this problem we propose Higher Order Hybrid Automata and its compositional execution semantics. Using this semantics a novel numerical simulation approach for hybrid systems is developed. The key idea is to approximate the guard and Ordinary Differential Equations with Taylor polynomials so as to accurately detect zero-crossings induced by the guards. Simulation results show that systems with transcendental guards can be simulated using our approach efficiently, while maintaining high simulation fidelity.

Freestyle Deliberate Practice Cadaveric Hand Surgery Simulation Training for Orthopedic Residents: Cohort Study.

BackgroundCadaveric simulation training may be part of the solution to reduced quantity and quality of operative surgical training in the modern climate. Cadaveric simulation allows the early part of the surgical learning curve to be moved away from patients into the laboratory, and there is a growing body of evidence that it may be an effective adjunct to traditional methods for training surgical residents. It is typically resource constrained as cadaveric material and facilities are expensive. Therefore, there is a need to be sure that any given cadaveric training intervention is maximally impactful. Deliberate practice (DP) theory as applied to cadaveric simulation training might enhance the educational impact.ObjectiveThe objectives of this study were (1) to assess the impact of a freestyle DP cadaveric hand surgery simulation training intervention on self-reported operative confidence for 3 different procedures and (2) to assess the subjective transfer validity, perceived educational value, and simulation fidelity of the training.MethodsThis study used validated questionnaires to assess the training impact on a cohort of orthopedic residents. The freestyle course structure allowed the residents to prospectively define personalized learning objectives, which were then addressed through DP. The study was conducted at Keele Anatomy and Surgical Training Centre, a medical school with an integrated cadaveric training laboratory in England, United Kingdom. A total of 22 orthopedic surgery residents of postgraduate year (PGY) 5-10 from 3 regional surgical training programs participated in this study.ResultsThe most junior (PGY 5-6) residents had the greatest self-reported confidence gains after training for the 3 procedures (distal radius open reduction internal fixation, flexor tendon repair, ulnar shortening osteotomy), and these gains diminished with resident seniority. The confidence gains were proportional to the perceived procedural complexity, with the most complex procedure having the lowest pretraining confidence score across all experience levels, and the greatest confidence increase in posttraining. Midstage (PGY 7-8) residents reported receiving the highest level of educational benefit from the training but perceived the simulation to be less realistic, compared to either the junior or senior residents. The most senior residents (PGY 9-10) reported the greatest satisfaction with the self-directed, freestyle nature of the training. All groups reported that they were extremely likely to transfer their technical skill gains to their workplace, that they would change their current practice based on these skills, and that their patients would benefit as a result of their having undertaken the training.ConclusionsFreestyle, resident-directed cadaveric simulation provides optimum DP conditions whereby residents can target their individualized learning needs. By receiving intensive, directed feedback from faculty, they can make rapid skill gains in a short amount of time. Subjective transfer validity potential from the training was very high, and objective, quantitative evidence of this is required from future work.

The Lifecycle of a Clinical Cadaver: A Practice-Based Ethnography

Phenomenon Cadavers have long played an important and complex role in medical education. While research on cadaver-based simulation has largely focused on exploring student attitudes and reactions or measuring improvements in procedural performance, the ethical, philosophical, and experiential aspects of teaching and learning with cadavers are rarely discussed. In this paper, we shed new light on the fascinating philosophical moves in which people engage each and every time they find themselves face to face with a cadaver. Approach Over a two-year period (2018/19–2019/20), we applied ethnographic methods (137 hours of observation, 24 interviews, and the analysis of 22 documents) to shadow the educational cadaver through the practical stages involved in cadaver-based simulation: 1. cadaver preparation, 2. cadaver-based skill practice with physicians and residents, and 3. interment and memorial services. We used Deleuze and Guattari’s concepts of becoming and acts of creation to trace the ontological “lifecycle” of an educational cadaver as embedded within everyday work practices. Findings We delineated six sub-phases of the lifecycle, through which the cadaver transformed ontologically from person to donor, body, cadaver, educational cadaver, teacher, and loved one/legacy. These shifts involved a network of bureaucratic, technical, educational, and humanistic practices that shaped the way the cadaver was perceived and acted upon at different moments in the lifecycle. By highlighting, at each phase, 1) the ontological transitions of the cadaver, itself, and 2) the practices, events, settings, and people involved in each of these transitions, we explored questions of “being” as it related to the ontological ambiguity of the cadaver: its conceptualization as both person and tool, simultaneously representing life and death. Insights Engaging deeply with the philosophical questions of cadaver-based simulation (CBS) helped us conceptualize the lifecycle as a series of meaningful and purposeful acts of becoming. Following the cadaver from program entry to interment allowed us to contemplate how its ontological ambiguity shapes every aspect of cadaver-based simulation. We found that in discussions of fidelity in medical simulation, beyond both the physical and functional, it is possible to conceive of a third type: ontological . The humanness of the cadaver makes CBS a unique, irreplaceable, and inherently philosophical, practice.

Opposite Effect of Cyclic Loading on the Material Properties of Medial Collateral Ligament at Different Temperatures: An Animal Study.

In traffic accidents, the medial collateral ligament (MCL) injury of the knee joint of pedestrians is common. Biofidelic material is important to realize MCL’s native biomechanics in simulations to clarify the injury mechanisms of pedestrians. Pedestrians’ MCLs usually experience cyclic loading at the intra-articular temperature of the knee joint before accidents. Temperature influences the material behaviors of ligaments. However, the mechanical properties of ligaments under cyclic loading have been widely evaluated only at room temperature rather than physiological temperature. Therefore, this study aimed to determine whether the difference between room and intra-articular temperatures influences the effect of cyclic loading on the mechanical properties of MCL. We measured the tensile properties of 34 porcine MCLs at room temperature (21–23°C) and intra-articular temperature (35–37°C), with either 10 cycles or 240 cycles of cyclic loading, a total of four different conditions. The structural responses and geometric data were recorded. After 240 cycles of cyclic loading, stiffness increased by 29.0% (p < 0.01) at room temperature and decreased by 11.5% (p = 0.106) at intra-articular temperature. Material properties were further compared because the geometric differences between samples were inevitable. At room temperature, after 240 cycles of cyclic loading, elastic modulus increased by 29.6% (p < 0.001), and failure strain decreased by 20.4% (p < 0.05). By contrast, at intra-articular temperature, after 240 cycles of cyclic loading, modulus decreased by 27.4% (p < 0.001), and failure strain increased by 17.5% (p = 0.193), insignificant though. In addition, there were no significant differences between the four groups in other structural or material properties. The results showed that temperature reversed the effect of cyclic loading on the mechanical properties of MCL, which may be caused by the high strength and thermally stable crosslinks of MCL. Therefore, for improving the fidelity of knee joint simulations and elucidating the injury mechanism of pedestrians, it is better to measure the mechanical properties of MCL at intra-articular temperature rather than room temperature.