Hopsan: An Open-Source Tool for Rapid Modelling and Simulation of Fluid and Mechatronic Systems

Author(s):  
Robert Braun ◽  
Peter Nordin ◽  
Liselott Ericson ◽  
L. Viktor Larsson ◽  
Petter Krus ◽  
...  

Abstract Hopsan is an open-source simulation package developed as a collaboration project between industry and academia. The simulation methodology is based on transmission line modelling, which provides several benefits such as linear model scalability, numerical robustness and parallel simulation. All sub-models are pre-compiled, so that no compilation is required prior to starting a simulation. Default component libraries are available for hydraulic, mechanic, pneumatic, electric and signal domains. Custom components can be written in C++ or generated from Modelica and Mathematica. Support for simulation-based optimization is provided using population-based, evolutionary or direct-search algorithms. Recent research has largely focused on co-simulation with other simulation tools. This is achieved either by using the Functional Mock-up Interface standard, or by tool-to-tool communications. This paper provides a description of the program and its features, the current status of the project, and an overview of recent and ongoing use cases from industry and academia.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Mohammadreza Yaghoobi ◽  
Krzysztof S. Stopka ◽  
Aaditya Lakshmanan ◽  
Veera Sundararaghavan ◽  
John E. Allison ◽  
...  

AbstractThe PRISMS-Fatigue open-source framework for simulation-based analysis of microstructural influences on fatigue resistance for polycrystalline metals and alloys is presented here. The framework uses the crystal plasticity finite element method as its microstructure analysis tool and provides a highly efficient, scalable, flexible, and easy-to-use ICME community platform. The PRISMS-Fatigue framework is linked to different open-source software to instantiate microstructures, compute the material response, and assess fatigue indicator parameters. The performance of PRISMS-Fatigue is benchmarked against a similar framework implemented using ABAQUS. Results indicate that the multilevel parallelism scheme of PRISMS-Fatigue is more efficient and scalable than ABAQUS for large-scale fatigue simulations. The performance and flexibility of this framework is demonstrated with various examples that assess the driving force for fatigue crack formation of microstructures with different crystallographic textures, grain morphologies, and grain numbers, and under different multiaxial strain states, strain magnitudes, and boundary conditions.



Author(s):  
Robert L. Grant ◽  
Bob Carpenter ◽  
Daniel C. Furr ◽  
Andrew Gelman

In this article, we present StataStan, an interface that allows simulation-based Bayesian inference in Stata via calls to Stan, the flexible, open-source Bayesian inference engine. Stan is written in C++, and Stata users can use the commands stan and windowsmonitor to run Stan programs from within Stata. We provide a brief overview of Bayesian algorithms, details of the commands available from Statistical Software Components, considerations for users who are new to Stan, and a simple example. Stan uses a different algorithm than bayesmh, BUGS, JAGS, SAS, and MLwiN. This algorithm provides considerable improvements in efficiency and speed. In a companion article, we give an extended comparison of StataStan and bayesmh in the context of item response theory models.



2019 ◽  
Vol 54 (9) ◽  
pp. 1884-1893 ◽  
Author(s):  
Ebrahim Adnan Patel ◽  
Abdullatif Aydın ◽  
Ashish Desai ◽  
Prokar Dasgupta ◽  
Kamran Ahmed


2021 ◽  
Author(s):  
Juliana Fernandes ◽  
Beatriz Machado ◽  
Cassio Cardoso-Filho ◽  
Juliana Nativio ◽  
Cesar Cabello ◽  
...  

Abstract Background This study aims to assess breast cancer survival rates after one decade of mammography in a large urban area of Brazil. Methods It is a population-based retrospective cohort of women with breast cancer in Campinas, São Paulo, from 2010 to 2014. Age, vital status and stage were accessed through the cancer and mortality registry, and patients records. Statistics used Kaplan-Meier, log-rank and Cox's regression. Results Out of the 2,715 cases, 665 deaths (24.5%) were confirmed until early 2020. The mean age at diagnosis was 58.6 years. Women 50-69 years were 48.0%, and stage I the most frequent (25.0%). The overall mean survival was 8.4 years (8.2-8.5). The 5-year survival (5yOS) for overall, 40-49, 50-59, 60-69, 70-79 years was respectively 80.5%, 87.7%, 83.7%, 83.8% and 75.5%. The 5yOS for stages 0, I, II, III and IV was 95.2%, 92.6%, 89.4%, 71.1% and 47.1%. There was no significant difference in survival in stage I or II (p=0.058). Compared to women 50-59 years, death's risk was 2.3 times higher for women 70-79 years and 26% lower for women 40-49 years. Concerning stage I, the risk of death was 1.5, 4.1 and 8.6 times higher, and 34% lower, respectively, for stage II, III, IV and 0. Conclusions In Brazil, breast cancers are currently diagnosed in the early stages, although advanced cases persist. Survival rates may reflect improvements in screening, early detection and treatment. The results can reflect the current status of other regions or countries with similar health care conditions.



2021 ◽  
Vol 12 (3) ◽  
pp. 122 ◽  
Author(s):  
Ricardo Ewert ◽  
Alexander Grahle ◽  
Kai Martins-Turner ◽  
Anne Magdalene Syré ◽  
Kai Nagel ◽  
...  

Electrification is a potential solution for transport decarbonization and already widely available for individual and public transport. However, the availability of electrified commercial vehicles like waste collection vehicles is still limited, despite their significant contribution to urban emissions. Moreover, there is a lack of clarity whether electric waste collection vehicles can persist in real world conditions and which system design is required. Therefore, we introduce a multi-agent-based simulation methodology to investigate the technical feasibility and evaluate environmental and economic sustainability of an electrified urban waste collection. We present a synthetic model for waste collection demand on a per-link basis, using open available data. The tour planning is solved by an open-source algorithm as a capacitated vehicle routing problem (CVRP). This generates plausible tours which handle the demand. The generated tours are simulated with an open-source transport simulation (MATSim) for both the diesel and the electric waste collection vehicles. To compare the life cycle costs, we analyze the data using total cost of ownership (TCO). Environmental impacts are evaluated based on a Well-to-Wheel approach. We present a comparison of the two propulsion types for the exemplary use case of Berlin. And we are able to generate a suitable planning to handle Berlin’s waste collection demand using battery electric vehicles only. The TCO calculation reveals that the electrification raises the total operator cost by 16–30%, depending on the scenario and the battery size with conservative assumptions. Furthermore, the greenhouse gas emissions (GHG) can be reduced by 60–99%, depending on the carbon footprint of electric power generation.



2012 ◽  
pp. 1196-1217
Author(s):  
Avi Messica

This chapter reviews the current status of Open Source (OS) and provides new insights into the prerequisites of the OS process as well as the profile of OS contributors. Moreover, it extends the scope of possible business models such to augment those that exist or were already discussed in the past. While the term OS was coined in the context of software development and redistribution, this chapter presents and discusses the concept of OS to include any Open Collaborative Innovation in both software and hardware.



2013 ◽  
Vol 2013 (1) ◽  
pp. 000094-000099 ◽  
Author(s):  
Laura Mirkarimi ◽  
Rajesh Katkar ◽  
Ron Zhang ◽  
Rey Co ◽  
Zhijun Zhao

We are developing a new solution for wide I/O package on package applications, which is Bond Via Array (BVA) technology. The prototype vehicle built in this study has 1020 I/O's at a pitch of 0.24 mm with a high aspect ratio of approximately 10:1 and is ≤1.4 mm tall. PoP applications require large bandwidth and thinner packages challenging package developers to address warpage control for high yield processes. The design optimization of this package was established through rigorous finite element analysis of materials selection and structural modifications. The simulation methodology was validated by measuring the warpage as a function of temperature for the experimental prototypes. The details for the simulation and verification processes for the wide I/O process will be discussed. The variation between finite element analysis predictions and the experimental builds was ~10%, which allowed us to complete package design optimization with our simulation tools. The prototype build includes a standard and a low CTE substrate.



2017 ◽  
Vol 8 (4) ◽  
pp. 41 ◽  
Author(s):  
Anjana P Das ◽  
Sabu M Thampi

In underwater sensor network(UWSN) research, it is highly expensive to deploy a complete test bed involving complex network structure and data links to validate a network protocol or an algorithm. This practical challenge points to the need of a simulation environment which can reproduce the actual underwater scenario without the loss of generality. Since so many simulators are proposed for UWSN simulation, the selection of an appropriate tool based on the research requirement is very important in validation and interpretation of results. This paper provides an in-depth survey of different simulation tools available for UWSN simulation. We compared the features offered by each tool, pre-requirements, and provide the run time experiences of some of the open source tools. We conducted simulation of sample scenarios in some of the open source tools and compared the results. This survey helps a researcher to identify a simulation tool satisfying their specific research requirements.



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