An evidence theory-based validation method for models with multivariate outputs and uncertainty

SIMULATION ◽  
2021 ◽  
pp. 003754972110228
Author(s):  
Wei Li ◽  
Shenglin Lin ◽  
Xiaochao Qian ◽  
Ping Ma ◽  
Ming Yang

Researchers usually rely on simulations to predict the response of complex systems, we recognize that the models that underlie these simulations are never perfect. Model validation is a crucial ingredient in simulation credibility assessment. Multivariate responses under uncertainty often exist in complex simulation model, and the corresponding validation problem is not be solved effectively based on the existing validation methods. Hence, this paper presents a new validation method based on evidence theory for simulation model under uncertainty. For analyzing the extent of agreement between simulation outputs and experimental observations under uncertainty, the data features of system responses under uncertainty are extracted primarily. Next, the validation data such as large sample, small sample, data features, and expert opinions are represented as evidence theory. Then the traditional evidence distance method is improved to measure the agreement extent of simulation outputs and experimental observations. The proposed method is verified through an application example on validation of a simulation model about the terminal guidance stage of flight vehicle to illustrate their validity and potential benefits.

2013 ◽  
Vol 300-301 ◽  
pp. 32-35
Author(s):  
Xiao Wen Zeng ◽  
Cheng Zeng ◽  
Bing Han

In order to manage the complex simulation data management in the process of mechanical dynamics simulation, a new management model was presented which is Performance Simulation Model(PSM). The model was based on PDM product structure and the concepts and elements of PSM were defined in this paper. Furthermore, the functional framework of PSM was proposed which based on the hierarchical relationship of product structure and the data stream relationship of data structure matrix. Finally, PSM was applied on ship planetary reducer collaborative simulation platform. The result indicates that the simulation data in mechanical collaborative simulation are managed by PSM, and the problem of interaction between collaborative simulation and PDM is solved.


2021 ◽  
Vol 144 (3) ◽  
Author(s):  
Matthias Joppa ◽  
Mike Bermuske ◽  
Frank Rüdiger ◽  
Lars Büttner ◽  
Jochen Fröhlich ◽  
...  

Abstract Impinging circular free-surface water jets are used in challenging cooling and cleaning tasks. In order to develop simulation models for process optimization, validation data are required, which are currently not available. Therefore, the flow field of these jets is studied for the first time with the novel laser Doppler velocity profile sensor. The mean velocity field and fluctuations are measured within the stagnation and adjacent redirection region for radial coordinates up to three times the nozzle diameter. In the examined parameter range with jet velocities up to 17 m/s and nozzle diameters up to 5.2 mm, i.e., Reynolds numbers up to 69 500, thin films of a few hundred micrometers are formed, which hinder the measurement with common optical measuring systems. Based on the measurement results, a comparatively low-cost volume of fluid simulation model is developed and validated that presumes a relaminarized film flow. The profiles measured and the simulated flow show very good agreement. In the future, the simulation model provides a basis for process optimization and the innovative measurement technology used will prospectively provide further detailed insights into other flows with high velocity gradients.


2020 ◽  
Vol 143 ◽  
pp. 02015
Author(s):  
Li Zherui ◽  
Cai Huiwen

Sea ice classification is one of the important tasks of sea ice monitoring. Accurate extraction of sea ice types is of great significance on sea ice conditions assessment, smooth navigation and safty marine operations. Sentinel-2 is an optical satellite launched by the European Space Agency. High spatial resolution and wide range imaging provide powerful support for sea ice monitoring. However, traditional supervised classification method is difficult to achieve fine results for small sample features. In order to solve the problem, this paper proposed a sea ice extraction method based on deep learning and it was applied to Liaodong Bay in Bohai Sea, China. The convolutional neural network was used to extract and classify the feature of the image from Sentinel-2. The results showed that the overall accuracy of the algorithm was 85.79% which presented a significant improvement compared with the tranditional algorithms, such as minimum distance method, maximum likelihood method, Mahalanobis distance method, and support vector machine method. The method proposed in this paper, which combines convolutional neural networks and high-resolution multispectral data, provides a new idea for remote sensing monitoring of sea ice.


2005 ◽  
Vol 37 (2) ◽  
pp. 425-431 ◽  
Author(s):  
James W. Richardson ◽  
Joe L. Outlaw

The provision for producers to update base acres and payment yields in the 2002 farm bill afforded an opportunity to test whether it was feasible to deliver a complex simulation model directly to producers. A Monte Carlo simulation model for assessing the economic impacts of the alternative base and yield options on individual farms was developed and made available to producers via the World Wide Web. The experiences and challenges from this collaborative extension and research effort are described, as well as the issues educators might consider before delivering complex software to a national audience via the Web.


2017 ◽  
Vol 31 (1) ◽  
pp. 38-48 ◽  
Author(s):  
Kaitlin N. Harkess ◽  
Paul Delfabbro ◽  
Jane Mortimer ◽  
Zara Hannaford ◽  
Sarah Cohen-Woods

Abstract. This paper evaluates the results of a longitudinal investigation of the potential benefits of yoga in a nonclinical sample of chronically stressed women (N = 116). Women undertook a twice weekly, hour-long yoga class for a period of 2 months, measuring psychological and physical indicators of health periodically. Changes in both areas were compared against a wait-list control group. The reported energy expenditure between groups was estimated to be similar, which suggests that the control group engaged in physical activities other than yoga. Of the six psychological outcomes measured, we found improvements in three. Specifically, those in the practicing yoga group experienced increases in positive affect, decreases in levels of distress and stress, as well as a decrease in waist circumference and increased flexibility. No between-group differences were found in mindfulness, well-being, and negative affect. These findings are generally consistent with an emerging literature, suggesting that yoga may provide both psychological and physiological effects that extend beyond its more obvious physical benefits, and are discussed in terms of the body’s allostatic load. These results should be considered in light of this study’s limitations, which include its small sample size, lack of an “active” control group, and female-only participants.


2007 ◽  
Vol 13 (5) ◽  
pp. 217-220 ◽  
Author(s):  
Trevor G Russell

Telerehabilitation is the provision at a distance of rehabilitation services such as physiotherapy, speech pathology or occupational therapy. The primary aim is to provide equitable access to rehabilitation services. Broadly speaking, the technologies used for telemedicine-based physical rehabilitation can be classified as: (1) image-based telerehabilitation; (2) sensor-based telerehabilitation; and (3) virtual environments and virtual reality telerehabilitation. To date, much of the research has been technology focused, and has consisted of single case or small sample research designs. The next step is to demonstrate viable telerehabilitation services in real world environments using well controlled research methodologies with large patient cohorts. In addition, the broader issues of cost-benefit and cost-effectiveness require investigation. If this can be done, then the undoubted potential benefits of telerehabilitation, for both the patient and health-care systems, can be realized.


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