Combining bootstrap-based stroke incidence models with discrete event modeling of travel-time and stroke treatment: Non-normal input and non-linear output

2017 ◽  
Author(s):  
Kim Rand-Hendriksen ◽  
Joe Viana ◽  
Fredrik Dahl
Keyword(s):  
Travel Time ◽  
Discrete Event ◽  
Stroke Incidence ◽  
Stroke Treatment ◽  
Event Modeling ◽  
Non Linear ◽  
Normal Input

Discrete-event modeling by system dynamics method

2021 ◽  
Author(s):  
A. N. Medvedev ◽  
V. N. Timokhin ◽  
Yu. A. Nelyubina
Keyword(s):  
System Dynamics ◽  
Discrete Event ◽  
Event Modeling ◽  
Dynamics Method

scholarly journals Combined approach architecture development to simulation modeling of systems with parallelism

2021 ◽  
Vol 4 (4(112)) ◽  
pp. 74-82
Author(s):  
Oksana Suprunenko
Keyword(s):  
Petri Nets ◽  
Dynamic Properties ◽  
Discrete Event ◽  
Structural Similarity ◽  
Integral Model ◽  
Combined Approach ◽  
Dynamic Simulations ◽  
Holistic Model ◽  
Event Modeling ◽  
Analytical Tools

Paradigms and graphical-analytical tools for building simulation tools and forming the architecture of a combined approach to studying the dynamic properties of systems with parallelism are described. An extension of the formal language of Petri nets is presented, which has greater modeling power than WF nets. The properties of hierarchical Petri nets are used to synthesize a holistic model. Discrete-event modeling and modeling of dynamic systems, which allow reflecting the quantitative and qualitative characteristics of the elements of the systems under study, served as the basis for the combined approach to the simulation of systems with parallelism. On their basis, graphic-analytical tools are proposed that provide the ability to describe the modeled system, adhering to the principle of structural similarity. They have dynamic simulations that make it easy to visually analyze and correct the model. Also, the proposed toolkit provides for the analysis of the dynamic properties of the model, which makes it possible to identify accumulated phenomena that can lead to unpredictability of the system’s functioning. A conceptual model for the synthesis and analysis of systems with parallelism is proposed, which provides for the construction of the components of the model based on the architecture. Their step-by-step analysis and the formation of an integral model of the software system are carried out using a network representation, according to the matrix description of which invariants are calculated. The analysis of invariants allows one to obtain the dynamic properties of the model and determine the localization of structures that lead to critical situations when they are detected. The architecture of the combined approach to the simulation of systems with parallelism is built, which provides the study of their dynamic properties to improve the reliability of the functioning of software systems

scholarly journals A National Study of the Quantity and Cost of Informal Caregiving for the Elderly with Stroke

Stroke ◽  
2001 ◽  
Vol 32 (suppl_1) ◽  
pp. 326-326
Author(s):  
Susan L Hickenbottom ◽  
Kenneth M Langa ◽  
Jeffrey S Kutcher ◽  
Mohammed U Kabeto ◽  
A. M Fendrick ◽  
...  
Keyword(s):  
Informal Care ◽  
Annual Cost ◽  
The Elderly ◽  
Informal Caregiving ◽  
National Study ◽  
Stroke Severity ◽  
Stroke Patients ◽  
Stroke Incidence ◽  
Stroke Treatment ◽  
The Us

56 Background: As the US population ages, increased stroke incidence will result in higher stroke-associated costs. While estimates of direct costs exist, little information is available regarding informal caregiving costs for stroke patients. Objective: To determine a nationally representative estimate of the quantity and cost of informal caregiving for elderly stroke patients. Methods: We used data from the first wave (1993) of the Asset and Health Dynamics (AHEAD) Study, a longitudinal study of people over 70 living in the community, to determine average weekly hours of informal caregiving. Multivariate and logistic regression analyses were performed to examine association of stroke and other covariates and assess the probability of receiving informal care. Average annual cost for informal caregiving was calculated. Results: Of the 7443 respondents, 656 (6%) reported a history of stroke. Of those, 375 (57%) reported stroke-related health problems (SRHP). After adjusting for cormorbid conditions, social support and sociodemographics, the proportion of patients receiving informal care increased with stroke severity, and there was a significant association of weekly hours of caregiving with stroke category (p<0.01). Using the mean 1998 wage for a home health aide ($8.20/hr.) as the value for family caregiver time, the expected yearly caregiving cost per stroke ranged from $3500 to $7600, which would result in an annual cost of more than $5.7 billion for stroke-related informal caregiving in the US. Conclusions: The economic burden of informal caregiving following stroke has not been studied previously. Informal caregiving occurs frequently; associated costs are substantial and should be considered when estimating the cost of stroke treatment.

Abstract 153: Novel Machine Learning Proves Stroke Risk is Not Linear

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Agni Orfanoudaki ◽  
Amre M Nouh ◽  
Emma Chesley ◽  
Christian Cadisch ◽  
Barry Stein ◽  
...  
Keyword(s):  
Machine Learning ◽  
Risk Factors ◽  
Risk Score ◽  
Stroke Risk ◽  
Assessment Tools ◽  
Risk Calculator ◽  
Stroke Incidence ◽  
Non Linear ◽  
User Friendly ◽  
The Impact

Background: Current stroke risk assessment tools presume the impact of risk factors is linear and cumulative. However, both novel risk factors and their interplay influencing stroke incidence are difficult to reveal using traditional linear models. Objective: To improve upon the Revised-Framingham Stroke Risk Score and design an interactive non-linear Stroke Risk Score (NSRS). Our work aimed at increasing the accuracy of event prediction and uncovering new relationships in an interpretable user-friendly fashion. Methods: A two phase approach was used to develop our stroke risk score predictor. First, clinical examinations of the Framingham offspring cohort were utilized as the training dataset for the predictive model consisting of 14,196 samples where each clinical examination was considered an independent observation. Optimal Classification Trees (OCT) were used to train a model to predict 10-year stroke risk. Second, this model was validated with 17,527 observations from the Boston Medical Center. The NSRS was developed into an online user friendly application in the form of a questionnaire (http://www.mit.edu/~agniorf/files/questionnaire_Cohort2.html). Results: The algorithm suggests a key dichotomy between patients with or without history of cardiovascular disease. While the model agrees with known findings, it also identified 23 unique stroke risk profiles and introduced new non-linear relationships; such as the role of T-wave abnormality on electrocardiography and hematocrit levels in a patient’s risk profile. Our results in both the training and validation populations suggested that the non-linear approach significantly improves upon the existing revised Framingham stroke risk calculator in the c-statistic (training 87.43% (CI 0.85-0.90) vs. 73.74% (CI 0.70-0.76); validation 75.29% (CI 0.74-0.76) vs 65.93% (CI 0.64-0.67), even in multi-ethnicity populations. Conclusions: We constructed a highly predictive, interpretable and user-friendly stroke risk calculator using novel machine-learning uncovering new risk factors, interactions and unique profiles. The clinical implications include prioritization of risk factor modification and personalized care improving targeted intervention for stroke prevention.

Hybrid simulation model for navigation performance evaluation of the Three Gorges–Gezhouba Dams under novel regulations

SIMULATION ◽  
2022 ◽  
pp. 003754972110725
Author(s):  
Yu Zhang ◽  
Hongwei Tian ◽  
Ran Li ◽  
Xiaolei Liang ◽  
Jun Li
Keyword(s):  
Simulation Model ◽  
Yangtze River ◽  
Discrete Event ◽  
Hybrid Simulation ◽  
Three Gorges ◽  
The Yangtze River ◽  
Validity And Reliability ◽  
Wet Season ◽  
Event Modeling ◽  
The Three Gorges

As an important project on the golden waterway of the Yangtze River in China, the Three Gorges–Gezhouba Dams (TGGD) plays a pivotal role in the construction of the Yangtze River Economic Belt. To improve the efficiency and safety of ship traffic, some novel navigation regulations have been implemented that change the TGGD operation obviously. For example, a piecewise control strategy proposed in the regulations is applied to control the traffic flow of ships under a sectional manner. With the implementation of these regulations, how to understand the dynamic effects of new changes on TGGD has been an important problem. The purpose of this work is to evaluate the navigation performance of the TGGD via a data- and event-driven hybrid simulation model developed by multi-agent and discrete-event modeling theories. The model simulates the three significant navigable scenarios inherent in the actual operating environment: dry season, wet season, and flood season, reflecting the real situations. The input data come from the statistical analysis of the actual navigation data provided by the Three Gorges Navigation Administration. The validity and reliability of the model are verified by comparing the output results with actual data. Moreover, a set of test experiments are designed to explore the TGGD navigation limit and analyze the key factors that restrict the navigation capacity of the TGGD system. The work is expected to provide a certain decision support for the future cooperative scheduling optimization of the TGGD.

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