Improvement of the Zienkiewicz–Zhu Error Recovery Technique Using a Patch Configuration

The Zienkiewicz–Zhu (ZZ) super-convergent patch recovery technique based on a node neighborhood patch configuration is used most widely for recovery of the stress field of a finite element analysis. In this study, an improved ZZ recovery technique using element neighborhood patch configuration is proposed. The improved recovery procedure is based on recovery of the stress field in the least-squares sense over an element patch that consists of the union of the elements surrounding the element under consideration. The proposed patch configuration provides more sampling points and improves the performance of the standard ZZ recovery technique. The effectiveness and reliability of the improved ZZ recovery approach is demonstrated through plane elastic and plastic plate problems. The problem domain is discretized with triangular and quadrilateral elements of different sizes. A comparison of the quality of error estimation using the ZZ recovery of derivative field and recovery of the displacement field using similar element neighborhood patch configurations is also presented. The numerical results show that the ZZ recovery technique and the displacement recovery technique, using a modified patch configuration, yield better results, convergence rate, and effectivity as compared with the standard ZZ super-convergent patch recovery technique. It is concluded that the improved ZZ recovery technique-based adaptive finite element analysis is very effective for converging a predefined accuracy with a significantly smaller number of degrees of freedom, especially in an elastic problem. It is also concluded that the improved ZZ recovery technique captures the plastic deformation problem solution errors more reliably than the standard ZZ recovery technique.

Error recovery training literature review: Implications for emergency field medicine

Training focused on recognizing when a medical procedure has not been implemented effectively may reduce preventable battlefield deaths. Although important research has been conducted about a range of error recovery training strategies, few studies have been conducted in the context of training for high stakes, dynamic domains such as combat medic training. We conducted a literature review to examine how error recovery training has been designed in other contexts, with the intent of abstracting recommendations for designing error recovery training to support military personnel providing emergency field medicine. Implications for combat medic training include: 1) a focus on error management rather than error avoidance, 2) a didactic training component may support training engagement and mental model development, 3) an experiential component may be designed to support perceptual skill development and anomaly detection, and 4) feedback should focus on allowing learners to make errors and encouraging them to learn from errors.

Information Source, Media Credibility, and Epidemic Control in COVID-19 Pandemic

Based on classic media theories and typical case studies, this paper analyzed the main media types and information sources in COVID-19 infections and the impacts on media trust and social trust, as well as the effects on public health prevention and national epidemic control. It found that news media, social media, aggregated media, medical media, and government media were the five main media types people used in this pandemic. News media performed well on professionalism, timeliness, closeness to public, and social support. Aggregated media and medical media also deserved public trust on error recovery, closeness to public, unselfishness, etc. The fake news on social media, inconsistent data, and information disclosure lag impaired public trust on media. Medical media promoted the health preventive behavior of the public. News media greatly influenced the agenda setting, public opinion, and national epidemic control in the COVID-19 pandemic.

Mesh Free Radial Point Interpolation Based Displacement Recovery Techniques for Elastic Finite Element Analysis

The study develops the displacement error recovery method in a mesh free environment for the finite element solution employing the radial point interpolation (RPI) technique. The RPI technique uses the radial basis functions (RBF), along with polynomials basis functions to interpolate the displacement fields in a node patch and recovers the error in displacement field. The global and local errors are quantified in both energy and L2 norms from the post-processed displacement field. The RPI technique considers multi-quadrics/gaussian/thin plate splint RBF in combination with linear basis function for displacement error recovery analysis. The elastic plate examples are analyzed to demonstrate the error convergence and effectivity of the RPI displacement recovery procedures employing mesh free and mesh dependent patches. The performance of a RPI-based error estimators is also compared with the mesh dependent least square based error estimator. The triangular and quadrilateral elements are used for the discretization of plates domains. It is verified that RBF with their shape parameters, choice of elements, and errors norms influence considerably on the RPI-based displacement error recovery of finite element solution. The numerical results show that the mesh free RPI-based displacement recovery technique is more effective and achieve target accuracy in adaptive analysis with the smaller number of elements as compared to mesh dependent RPI and mesh dependent least square. It is also concluded that proposed mesh free recovery technique may prove to be most suitable for error recovery and adaptive analysis of problems dealing with large domain changes and domain discontinuities.

The usability of a smartphone-based fall risk health application for adult wheelchair users (Preprint)

BACKGROUND Individuals who use wheelchairs and scooters rarely undergo fall risk screening. Mobile health technology is a possible avenue to provide fall risk assessments. The promise of this approach is dependent upon its usability. OBJECTIVE To determine the usability of a fall risk mobile health application and identify key technology development insights for aging adults who use wheeled devices. METHODS Two rounds (n=5/round) of usability testing utilizing an iterative design-evaluation process were performed. Participants completed the custom-designed fall risk application, Steady-Wheels™. To quantify fall risk, the application led participants through 12 demographic questions and three progressively challenging seated balance tasks. Once completed, participants shared insights on the application’s usability through semi-structured interviews and the completion of the Systematic Usability Scale (SUS). Testing sessions were recorded and transcribed. Codes were identified within transcriptions to create themes. Average SUS scores were calculated for each round. RESULTS The first round of testing yielded two main themes: ease of use and flexibility of design. SUS scores ranged from 72.5 to 97.5 with a mean (SD) of 84.5 (11.4). After modifications were made, the second round of testing yielded two new themes: application layout and clarity of instruction. SUS scores improved in the second iteration and ranged from 87.5 to 97.5 with a mean of 91.9 (4.3). CONCLUSIONS The mobile health application, Steady-Wheels, has excellent usability and the potential to provide adult wheeled device users with an easy-to-use, remote fall risk assessment tool. Characteristics that promoted such usability were guided navigation, large text and radio buttons, clear and brief instructions accompanied by representative illustrations, and simple error recovery. Intuitive fall risk reporting was achieved through the presentation of a single number located on a color-coordinated continuum with low, medium, and high-risk delineations.

PHY, MAC, and RLC Layer Based Estimation of Optimal Cyclic Prefix Length

This work is motivated by growing evidence that the standard Cyclic Prefix (CP) length, adopted in the Long Term Evolution (LTE) physical layer (PHY) specifications, is oversized in propagation environments ranging from indoor to typical urban. Although this ostensibly seems to be addressed by 5G New Radio (NR) numerology, its scalable CP length reduction is proportionally tracked by the OFDM symbol length, which preserves the relative CP overhead of LTE. Furthermore, some simple means to optimize fixed or introduce adaptive CP length arose from either simulations or models taking into account only the bit-oriented PHY transmission performance. On the contrary, in the novel crosslayer analytical model proposed here, the closed-form expression for the optimal CP length is derived such as to minimize the effective average codeblock length, by also considering the error recovery retransmissions through the layers above PHY—the Medium Access Control (MAC) and the Radio Link Control (RLC), in particular. It turns out that, for given protective coding, the optimal CP length is determined by the appropriate rms delay spread of the channel power delay profile part remaining outside the CP span. The optimal CP length values are found to be significantly lower than the corresponding industry-standard ones, which unveils the potential for improving the net throughput.