iterative refinement
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2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Ambrose H. Wong ◽  
Nasim S. Sabounchi ◽  
Hannah R. Roncallo ◽  
Jessica M. Ray ◽  
Rebekah Heckmann

Abstract Background Over 1.7 million episodes of agitation occur annually across the United States in emergency departments (EDs), some of which lead to workplace assaults on clinicians and require invasive methods like physical restraints to maintain staff and patient safety. Recent studies demonstrated that experiences of workplace violence contribute to symptoms of burnout, which may impact future decisions regarding use of physical restraints on agitated patients. To capture the dynamic interactions between clinicians and agitated patients under their care, we applied qualitative system dynamics methods to develop a model that describes feedback mechanisms of clinician burnout and the use of physical restraints to manage agitation. Methods We convened an interprofessional panel of clinician stakeholders and agitation experts for a series of model building sessions to develop the current model. The panel derived the final version of our model over ten sessions of iterative refinement and modification, each lasting approximately three to four hours. We incorporated findings from prior studies on agitation and burnout related to workplace violence, identifying interpersonal and psychological factors likely to influence our outcomes of interest to form the basis of our model. Results The final model resulted in five main sets of feedback loops that describe key narratives regarding the relationship between clinician burnout and agitated patients becoming physically restrained: (1) use of restraints decreases agitation and risk of assault, leading to increased perceptions of safety and decreasing use of restraints in a balancing feedback loop which stabilizes the system; (2) clinician stress leads to a perception of decreased safety and lower threshold to restrain, causing more stress in a negatively reinforcing loop; (3) clinician burnout leads to a decreased perception of colleague support which leads to more burnout in a negatively reinforcing loop; (4) clinician burnout leads to negative perceptions of patient intent during agitation, thus lowering threshold to restrain and leading to higher task load, more likelihood of workplace assaults, and higher burnout in a negatively reinforcing loop; and (5) mutual trust between clinicians causes increased perceptions of safety and improved team control, leading to decreased clinician stress and further increased mutual trust in a positively reinforcing loop. Conclusions Our system dynamics approach led to the development of a robust qualitative model that illustrates a number of important feedback cycles that underly the relationships between clinician experiences of workplace violence, stress and burnout, and impact on decisions to physically restrain agitated patients. This work identifies potential opportunities at multiple targets to break negatively reinforcing cycles and support positive influences on safety for both clinicians and patients in the face of physical danger.


Author(s):  
Leon Eifler ◽  
Ambros Gleixner

AbstractThe last milestone achievement for the roundoff-error-free solution of general mixed integer programs over the rational numbers was a hybrid-precision branch-and-bound algorithm published by Cook, Koch, Steffy, and Wolter in 2013. We describe a substantial revision and extension of this framework that integrates symbolic presolving, features an exact repair step for solutions from primal heuristics, employs a faster rational LP solver based on LP iterative refinement, and is able to produce independently verifiable certificates of optimality. We study the significantly improved performance and give insights into the computational behavior of the new algorithmic components. On the MIPLIB 2017 benchmark set, we observe an average speedup of 10.7x over the original framework and 2.9 times as many instances solved within a time limit of two hours.


2021 ◽  
Author(s):  
Adrienne B. Nicotra ◽  
Sonya R. Geange ◽  
Nur H. A. Bahar ◽  
Hannah Carle ◽  
Alexandra Catling ◽  
...  

AbstractThis paper reports on the design and evaluation of Field Studies in Functional Ecology (FSFE), a two-week intensive residential field course that engages students to master core content in functional ecology alongside skills that facilitate their transition from ‘student’ to ‘scientist’. This paper provides an overview of the course structure, showing how the constituent elements have been designed and refined over successive iterations of the course. We detail how FSFE students are guided first to develop their own research questions (Field Problems), and then through a structured reflective approach of rapid prototyping and iterative refinement of each stage of the research process. Using extensive evaluation data, we show how, coached by experts within a cognitive apprenticeship framework, FSFE students develop a coherent and nuanced understanding of how to approach and execute ecological studies. The sophisticated knowledge and skills as ecology researchers that they develop during the course is highlighted through high quality presentations and peer-reviewed publications in a student-led journal. We illustrate how field course elements can be used to provide cognitive, affective and reflective tools that allow students to gain maximum value from their educational journey, and the confidence to consider research in their future careers.


2021 ◽  
Vol 2131 (2) ◽  
pp. 022029
Author(s):  
Yu P Manshin ◽  
E Yu Manshina

Abstract Sufficient safety of the parts, which determines the safety of the system specified by the technical assignment, is the necessary quality of the project, the subject of the design engineer’s attention and the customer’s requirement. An extensive task is the collection of data for iterative refinement of the resource for project details in a probabilistic aspect. It can be significantly reduced when using approximate methods for estimating the resource at intermediate stages of refining the project to the required resource with a calculated probability of failure-free operation. Thus, by the analysis of dimensionless relations of parameters of models of fatigue damage development, it is possible to obtain tools of numerical estimation of technological and constructive techniques of increase of a resource of details and their rational combination. The paper deals with the numerical measures of various directions of upgrading the fatigue life of the parts, derived from the dimensionless relations of the parameters of fatigue damage development models.


2021 ◽  
Author(s):  
Yu M. Kulikov ◽  
E. E. Son

Abstract This paper considers the canonical problem of a thin shear layer evolution at Reynolds number Re = 400000 using the novel Compact Accurately Boundary Adjusting high-Resolution Technique (CABARET). The study is focused on the effect of the specific mesh refinement in the high shear rate areas on the flow properties under the influence of the developing instability. The original sequence of computational meshes (256^2, 512^2, 1024^2, 2048^2 cells) is modified using an iterative refinement algorithm based on the hyperbolic tangent. The properties of the solutions obtained are discussed in terms of the initial momentum thickness and the initial vorticity thickness, viscous and dilatational dissipation rates and also integral enstrophy. The growth rate for the most unstable mode depending on the mesh resolution is considered. In conclusion the accuracy of calculated mesh functions is estimated via L1, L2, L∞ norms.


2021 ◽  
Vol 2078 (1) ◽  
pp. 012038
Author(s):  
Junwei Hu ◽  
Jifeng Sun ◽  
Yinggang Li ◽  
Qi Zhang ◽  
Shuai Zhao ◽  
...  

Abstract This paper introduces a new binocular stereo deep learning network based on point cloud, which can realize higher precision point cloud reconstruction through continuous iteration of the network. Our method directly carries out point cloud processing on the target, calculates the difference between the current depth map and the real depth, estimates the loss according to the predicted point cloud and the information of the dual view input image, and then uses the appropriate loss function to iteratively process the point cloud. In addition, we can customize the number of iterations to achieve higher precision point cloud effect. The proposed network basically achieves good results on KITTI data set.


2021 ◽  
Vol 6 ◽  
pp. 122-128
Author(s):  
Sergey Smirnov ◽  
◽  

The problem of design of experiment with resource constraints is investigated. For a complex system intended for experimental research, before using the well known advanced methods of factorial design, you must first create a simplified mathematical model that represents an incomplete abbreviated description of the system. At the same time, on this simplification from all objectively existing independent parameters of the system remain only the most important parameters, which is a forced procedure due to the natural limitations of the resources available to perform the experimental study. The same constraints limit the number of values assigned to each of the parameters (factor levels number). The article is devoted to the modification of the existing method of discretization of such a model with a rational choice of discretization parameters in accordance with the existing limitations, but with an extremely unreliable in terms of convergence iterative solution procedure. The main ideas of the modified approach are as follows: 0) The choice of the number of levels of factors is proportional to the importance of the relevant parameters and the reduction to the problem of finding a fixed point (as in the known method). 1) Probability partition (instead of partition into equal length intervals) for discretization and selection of representative values of the parameter, which allows to find an exact simple expression for its Shannon entropy. 2) Transition from multi- to one-parameter (coefficient of proportionality as an indicator of parameterization) representation of nonlinear mapping, its decomposition and simplification of the iterative process. 3) Finding the initial value of the coefficient of proportionality for a factor with average relevance and calculations for other factors, followed by iterative refinement. The iterative process is guaranteed to coincide, because the consideration of small and large values of the scalar parameter allows us to use the theorem on the intermediate value of a continuous function. Then, with the help of the developed procedure, two tasks on the assignment of the number of factor levels for situations with small and large resource constraints are solved, the corresponding complications in the calculations and ways to overcome them are indicated.


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