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- Leong, Swee, et al.
(författare)
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A real world pilot implementation of the Core Manufacturing Simulation Data model
- 2008
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Ingår i: ; , s. 334-341
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Konferensbidrag (refereegranskat)abstract
- While software for discrete event simulation (DES) has emerged into sophisticated tools for decision support in a wide range of contexts, the need to integrate DES tools with other applications is increasing. In the industrial engineering context, simulation engineers strive to use real world data, e.g., logs of machine breakdown, to make behavior of DES models imitate reality. However, the format used for describing simulation data is often specialized to the current situation. The Core Manufacturing Simulation Data (CMSD) is a collaborative effort with academia and industry to standardize the format used for simulation data, to facilitate data exchange among simulation and manufacturing applications. This paper describes the results from a pilot implementation study at Volvo Trucks, where CMSD was utilized as the data exchange format between two data systems and two DES models. The DES tools used were commercial software packages Unigraphics Plant Simulation and InControl Enterprise Dynamics. Generic and reusable interfaces for CMSD-file communication were developed for each of these tools. The CMSD interfaces were successfully connected to a model in each simulation tool describing the same manufacturing process. A stand alone application was developed to collect and analyze raw data and to create the CMSD file being used as input data for both models. The result is a system including raw data analysis, data reformatting, CMSD interfacing, and model execution. Based on the result, a generic methodology for CMSD interface development in DES tools has evolved. The most important conclusion is that CMSD data can be interpretable by both Plant Simulation and Enterprise Dynamics, and that it saves engineering development time during the model building phase.
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- Lidberg, Simon, MSc. 1986-
(författare)
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Evaluating Fast and Efficient Modeling Methods for Simulation-Based Optimization
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As the industry in general, and the automotive industry in particular, is transforming -- due to new technologies and changes in market demands through electrification, digitalization, and globalization -- maintaining a competitive edge will require better predictions. Better predictions of production performance allows companies to capitalize on opportunities, avoid costly mistakes, and be proactive about change.A commonly used tool in manufacturing for the prediction of production performance is discrete-event simulation. In combination with artificial intelligence methods such as multi-objective optimization, in literature often referred to as simulation-based optimization, and knowledge extraction, bottlenecks in the production process can be identified and recipes for optimal improvement order can be obtained. These recipes support the decision-maker in both understanding the production system and improving it optimally in terms of resource efficiency and investment cost. Even though the use of simulation-based optimization is widespread on the production line level, use on the factory level is more scarce. Improvements on the production line level, without a holistic view of factory performance, can be suboptimal and may only lead to increased storage levels instead of increased output to the customer.The main obstacle for applying simulation-based optimization to the factory level is the complexity of its constituent parts, i.e., detailed production line models. Connecting several detailed production line models to create a factory model results in an overly complicated, albeit, accurate model. A single factory model running for one minute would equate to almost 140 days required for an optimization project, too long to provide decision-support relevant to manufacturing decision-making. This can be mitigated by parallel computing, but a more effective approach is to simplify the production line models to decrease the runtime while trying to maintain accuracy. Model simplification methods are approaches to reduce model complexity in new and existing simulation models. Previous research has provided an accurate and runtime efficient simplification method by use of a generic model structure built by common modeling components. Although the method seems promising in a few publications, it was lacking external and internal validity.This project presents simulation-based optimization on the factory level enabled by a model simplification method. By following the design science research methodology, several case-studies mainly in the automotive industry identify issues with the current implementation, propose additions to the method, and validates them.
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- Bernberg, Evelina, 1981, et al.
(författare)
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Social disruption stress increases IL-6 levels and accelerates atherosclerosis in ApoE-/- mice.
- 2012
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Ingår i: Atherosclerosis. - : Elsevier BV. - 0021-9150 .- 1879-1484. ; 221:2, s. 359-65
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Tidskriftsartikel (refereegranskat)abstract
- We have previously shown that different forms of stress have distinctive effects on atherogenesis in mice. We showed that social stress increase atherosclerosis in ApoE(-/-) mice, while more physical forms of stress do not. Here we evaluated the effect of social disruption (SDR) stress on atherogenesis and evaluated cytokine release after SDR-stress and five more physical stressors.
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- Eliason, Marcus, et al.
(författare)
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Forward-looking moral hazard in social insurance
- 2019
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Ingår i: Labour Economics. - : Elsevier BV. - 0927-5371 .- 1879-1034. ; 60, s. 84-98
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Tidskriftsartikel (refereegranskat)abstract
- This study tests for forward-looking moral hazard in the sickness insurance system by exploiting a 1991 reform in Sweden. The replacement rate was reduced for short absences but not for long absences, which introduced a potential future cost of returning to work. Using this exogenous variation in the replacement rate and controlling for dynamic selection, we find that the potential future cost of returning to work decreased the outflow from long-term sickness absence. This finding suggests that long-term sickness absentees respond to economic incentives and are forward-looking, which highlights the importance of taking forward-looking behavior into account when designing and evaluating social insurance programs.
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- González Chávez, Clarissa Alejandra, 1994, et al.
(författare)
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Achieving Sustainable Manufacturing by Embedding Sustainability KPIs in Digital Twins
- 2022
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Ingår i: Proceedings - Winter Simulation Conference. - 0891-7736. ; 2022-December, s. 1683-1694
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Konferensbidrag (refereegranskat)abstract
- The manufacturing industry requires highly flexible and dynamic production lines that shift from conventional mass production to cover the requirements and fulfill demands. Customized production may reduce production waste but has not been studied to a wide extent. The advancement of digital technologies, e.g., Digital Twins, enable factories to collect real-time data. Also, they can enable remote monitoring of the production processes by establishing bi-directional flows of data between the physical and virtual spaces. This study draws its sight to the potential of digital manufacturing to improve sustainability in production systems by making use of Digital Twins. This research work performs a literature review and identifies suitable KPIs for a DES model and evaluates the impact in a drone factory in four scenarios that test final assembly processes. The findings of this work can pose a first step toward the future development of a digital twin.
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- Herz, Marcus, 1978, et al.
(författare)
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Mot ett kritiskt socialt arbete
- 2022. - 2
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Ingår i: Kritiskt socialt arbete. - Malmö : Liber. - 9789147144235 ; , s. 214-228
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Bokkapitel (refereegranskat)
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- Jalo, Hoor, 1994, et al.
(författare)
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Early Characterization of Stroke Using Video Analysis and Machine Learning
- 2023
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Ingår i: Emerging Technologies in Healthcare and Medicine. - 9781958651926 ; 116:2023, s. 74-84
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Konferensbidrag (refereegranskat)abstract
- Stroke is one of the leading causes of death and disability worldwide and requires an immediate attention as the longer the patient is left untreated, the more sever its outcomes are. Enhancing access to optimal treatment and reducing mortality rates require improving the accuracy of stroke characterization methods in prehospital settings. This study explores how video analysis and machine learning (ML) can be leveraged to identify stroke symptoms on the National Institute of Health Stroke Scale (NIHSS), with the goal of facilitating the prehospital management of patients with suspected stroke. A total of 888 videos were captured from the research group members, who mimicked stroke symptoms including facial palsy, leg and arm paresis, ataxia and dysarthria, following the criteria of the NIHSS. Multiple algorithms, utilized in earlier studies, were examined to predict these symptoms, and their performance was assessed using accuracy, sensitivity and specificity. The best method for detecting facial palsy was found using Histogram of Oriented Gradients (HOG) features in conjunction with Adaptive Boosting (AdaBoost), achieving an accuracy, sensitivity and specificity values of 97.8%, 98.0% and 97.0%, respectively. The identification of arm paresis reached 100% on all metrics using a combination of MediaPipe and SVM. For leg paresis, all algorithms had poor detection rates. The outcome for ataxia for both limbs varied. Google Cloud Speech-to-Text was used to detect dysarthria and reached 100% on all evaluation metrics. These findings suggest that video analysis and ML have the potential to assist early stroke diagnosis, but further research is needed to validate this.
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- Kosen, Sandoko, 1991, et al.
(författare)
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Building blocks of a flip-chip integrated superconducting quantum processor
- 2022
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Ingår i: Quantum Science and Technology. - : IOP Publishing. - 2058-9565. ; 7:3
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Tidskriftsartikel (refereegranskat)abstract
- We have integrated single and coupled superconducting transmon qubits into flip-chip modules. Each module consists of two chips-one quantum chip and one control chip-that are bump-bonded together. We demonstrate time-averaged coherence times exceeding 90 mu s, single-qubit gate fidelities exceeding 99.9%, and two-qubit gate fidelities above 98.6%. We also present device design methods and discuss the sensitivity of device parameters to variation in interchip spacing. Notably, the additional flip-chip fabrication steps do not degrade the qubit performance compared to our baseline state-of-the-art in single-chip, planar circuits. This integration technique can be extended to the realisation of quantum processors accommodating hundreds of qubits in one module as it offers adequate input/output wiring access to all qubits and couplers.
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