Qualitative Simulation Studies Research Articles

Using Visual Patient to Show Vital Sign Predictions, a Computer-Based Mixed Quantitative and Qualitative Simulation Study.

Machine learning can analyze vast amounts of data and make predictions for events in the future. Our group created machine learning models for vital sign predictions. To transport the information of these predictions without numbers and numerical values and make them easily usable for human caregivers, we aimed to integrate them into the Philips Visual-Patient-avatar, an avatar-based visualization of patient monitoring. We conducted a computer-based simulation study with 70 participants in 3 European university hospitals. We validated the vital sign prediction visualizations by testing their identification by anesthesiologists and intensivists. Each prediction visualization consisted of a condition (e.g., low blood pressure) and an urgency (a visual indication of the timespan in which the condition is expected to occur). To obtain qualitative user feedback, we also conducted standardized interviews and derived statements that participants later rated in an online survey. The mixed logistic regression model showed 77.9% (95% CI 73.2-82.0%) correct identification of prediction visualizations (i.e., condition and urgency both correctly identified) and 93.8% (95% CI 93.7-93.8%) for conditions only (i.e., without considering urgencies). A total of 49 out of 70 participants completed the online survey. The online survey participants agreed that the prediction visualizations were fun to use (32/49, 65.3%), and that they could imagine working with them in the future (30/49, 61.2%). They also agreed that identifying the urgencies was difficult (32/49, 65.3%). This study found that care providers correctly identified >90% of the conditions (i.e., without considering urgencies). The accuracy of identification decreased when considering urgencies in addition to conditions. Therefore, in future development of the technology, we will focus on either only displaying conditions (without urgencies) or improving the visualizations of urgency to enhance usability for human users.

How Workplace Bullying and Incivility Impacts Patient Safety: A Qualitative Simulation Study Using BSN Students

BackgroundHealth care systems strive to provide safe and quality environments. Bullying and incivility are found internationally in health care environments and begins in academic education programs. This study evaluates the impact of a bullying simulation when students participated in different participant roles. MethodA convenience sample of 169 nursing students participated in a simulation and completed a postevaluation survey. Qualitative inductive methods were used to analyze responses. ResultsFour major themes were revealed: nurse and patient/family experience, advocacy strategies, and impact on patient outcomes. ConclusionsThe students learned that patient safety and outcomes are affected when bullying occurs. Students found the simulation meaningful.

Investigating Pervaporation for In Situ Acetone Removal as Process Intensification Tool in ω‐Transaminase Catalyzed Chiral Amine Synthesis

Hydrophobic pervaporation (PV), allowing for the separation of an organic component from an aqueous stream, was investigated for in situ acetone removal from a transamination reaction. A poly(dimethylsiloxane) membrane was applied in a coupled enzymatic process at 5 L scale. Among the four components, there was no loss of donor and product amines through PV which was highly desirable. However, in addition to removal of acetone, there was also an unwanted loss of acetophenone (substrate ketone) because of PV. The coupled enzyme-PV process resulted in 13% more product formation compared to the control process (where no PV was applied) after 9 h. Results from a qualitative simulation study (based on partial vapor pressures and a vapor-liquid equilibrium of the feed solution) indicated that PV might have an advantage over direct distillation strategy for selective removal of acetone from the reaction medium. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2731, 2019.

Precise positioning and assembly of metallic nanoclusters as building blocks of nanostructures: A molecular dynamics study

Molecular dynamics simulations are used to study the manipulation of metallic nanoclusters. These particles are assumed as potential building blocks for bottom-up manufacturing of nanoscale structures. One of the key factors in the assembly of nanoclusters is the precise positioning of them by a manipulation system. Prediction of the corresponding behavior under the influence of working conditions is of crucial importance for planning of controlled positioning and assembly of nanoclusters. The focus of the present research is on ultra-fine metallic nanoclusters. The effects of material type and manipulation strategy on the success of the process have been investigated by molecular dynamics. Such qualitative simulation studies can evaluate the chance of success of a certain nanopositioning scenario regarding different working conditions before consuming high experimental expenses.

Qualitative study of nanocluster positioning process: Planar molecular dynamics simulations

One of the key factors in the assembly of nanoclusters is the precise positioning of them by a manipulation system. Currently the size of clusters used as building blocks is shrinking down to a few nanometers. In such cases, the particle nature of matter plays an important role in the manipulator/cluster/substrate interactions. Having a deeper insight to the aforementioned nano-scale interactions is crucial for prediction and understanding of the behavior of nanoclusters during the positioning process. In the present research, 2D molecular dynamics simulations have been used to investigate such behaviors. Performing planar simulations can provide a fairly acceptable qualitative tool for our purpose while the computation time is greatly reduced in comparison to 3D simulations. The system consists of a tip, cluster and substrate. The focus of the present research is on ultra-fine metallic nanoclusters. To perform this research, Nose–Hoover dynamics and Sutton–Chen interatomic potential will be used to investigate the behavior of the above system which is made from different transition metals. The effects of material type, tip form and manipulation strategy on the success of the process have been investigated by planar molecular dynamics. Such qualitative simulation studies can evaluate the chance of success of a certain nanopositioning scenario regarding different working conditions before consuming large-scale computation time or high experimental expenses.

Targeting Safety Net Interventions in Developing Countries: Some Insights from a Qualitative Simulation Study from Malawi

This article presents the results of a study that simulated the implementation of targeted safety nets in Malawi. It was prompted by the proposal by the government of Malawi to establish a publicly supported safety net system in partnership with a consortium of donors, which would, among other things, operate on the basis of the principle of community targeting for purposes of maximising efficiency and effectiveness. The purpose of this study was therefore threefold: to find out whether communities could develop criteria for targeting beneficiaries; to establish whether communities could make decisions on who to include and exclude as beneficiaries on the basis of criteria identified; and to seek their views on how the safety net transfers could be efficiently and effectively managed. The results demonstrated that there is great resistance to targeting but nevertheless communities have clear ideas on whom to target and on how to make the selection and distribution processes fair, transparent and accountab...

Constructing Fault Trees for Advanced Process Control Systems—Application to Cascade Control Loops

A systematic approach to construct fault trees for advanced process control systems is presented in this paper. For illustration purpose, the proposed method is explained with a specific feedback scheme, i.e., the cascade control strategy. The digraph configuration of a standard system is first described and analyzed in detail. On the basis of a series of qualitative simulation studies, all failure mechanisms can be identified and summarized with a set of generalized fault-tree structures. The fault trees produced with the conventional digraph-based techniques are shown to be not as comprehensive as the ones constructed with the proposed approach. To demonstrate the correctness of our analysis, the successful application of the proposed structures to a heat exchange process is presented. In addition, the resulting fault tree is compared with one obtained from a single-loop feedback control system and the trade-off between the two in system reliability and control performance is assessed accordingly.

A procedure for establishing a reference state in qualitative simulation of operational systems

Identifies the need for a formal procedure to generate a reference state when conducting qualitative simulation studies. A procedure for generating a reference state is presented and justified. The procedure considers output performance indicators, steady state conditions, system capacity and model validity. Its application is illustrated using a simulation model for an order fulfillment process. The calibration process is necessarily iterative and subjective to some degree and in general does not generate a unique reference state. The impact of using different reference states in a simulation experiment is illustrated. In general the results are consistent when interpreted qualitatively in terms of direction, trend and order of magnitude. The approach is most applicable for qualitative simulation studies where comparative performance is being investigated and where precise numerical estimation is not required. However the procedure is also applicable to the study of real systems where data is not available.

Analog Computer Simulation of a Neural Element

As a prelude to the study of the adaptive-behavior and data-handling characteristics of natural and artificial neural networks, an analog model of a single neuron was developed. An analog computer was employed to reproduce the known electrical characteristics of a neuron in a qualitative simulation study of neuronal behavior. A self-imposed criterion of a minimum number of analog-computer components was adopted for the single-neuron simulation in anticipation of network studies. This criterion led to the development of a simple analog circuit which has qualitatively reproduced some of the known electrical characteristics of a neuron, such as: initiation of an action potential in the presence of suprathreshold depolarizing (or excitatory) inputs; strength-duration relationship; accommodation; refractoriness; rate of pulse repetition as a function of the input depolarization level; and prolonged action potentials. The simulation method adopted consisted of four major analog-computer components, three operational amplifiers and a single-shot multivibrator. The circuit developed has a linear forward path with a nonlinear form of feedback. A discussion is given of the properties exhibited by the simulated neuron with and without the nonlinear feedback. A mathematical method for linearly approximating nonlinear behavior is presented. This method is known as the describing function technique, and its application to the analysis of neuronal behavior is described, as well as the technique's application to the synthesis of simulation networks.