| 41. |
- Ebadi, Hamid, et al.
(författare)
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Efficient and Effective Generation of Test Cases for Pedestrian Detection - Search-based Software Testing of Baidu Apollo in SVL
- 2021
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Ingår i: 2021 IEEE International Conference on Artificial Intelligence Testing (AITest). - : IEEE. - 9781665434812 ; , s. 103-110
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Konferensbidrag (refereegranskat)abstract
- With the growing capabilities of autonomous vehicles, there is a higher demand for sophisticated and pragmatic quality assurance approaches for machine learning-enabled systems in the automotive AI context. The use of simulation-based prototyping platforms provides the possibility for early-stage testing, enabling inexpensive testing and the ability to capture critical corner-case test scenarios. Simulation-based testing properly complements conventional on-road testing. However, due to the large space of test input parameters in these systems, the efficient generation of effective test scenarios leading to the unveiling of failures is a challenge. This paper presents a study on testing pedestrian detection and emergency braking system of the Baidu Apollo autonomous driving platform within the SVL simulator. We propose an evolutionary automated test generation technique that generates failure-revealing scenarios for Apollo in the SVL environment. Our approach models the input space using a generic and flexible data structure and benefits a multi-criteria safety-based heuristic for the objective function targeted for optimization. This paper presents the results of our proposed test generation technique in the 2021 IEEE Autonomous Driving AI Test Challenge. In order to demonstrate the efficiency and effectiveness of our approach, we also report the results from a baseline random generation technique. Our evaluation shows that the proposed evolutionary test case generator is more effective at generating failure-revealing test cases and provides higher diversity between the generated failures than the random baseline.
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| 42. |
- Hamngren Blomqvist, Charlotte, 1984, et al.
(författare)
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Design and evaluation of a microfluidic system for inhibition studies of yeast cell signaling
- 2012
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Ingår i: Proceedings of SPIE. - : SPIE. - 0277-786X .- 1996-756X. - 9780819491756 ; , s. 84582K-
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Konferensbidrag (refereegranskat)abstract
- In cell signaling, different perturbations lead to different responses and using traditional biological techniques that result in averaged data may obscure important cell-to-cell variations. The aim of this study was to develop and evaluate a four-inlet microfluidic system that enables single-cell analysis by investigating the effect on Hog1 localization post a selective Hog1 inhibitor treatment during osmotic stress. Optical tweezers was used to position yeast cells in an array of desired size and density inside the microfluidic system. By changing the flow rates through the inlet channels, controlled and rapid introduction of two different perturbations over the cell array was enabled. The placement of the cells was determined by diffusion rates flow simulations. The system was evaluated by monitoring the subcellular localization of a fluorescently tagged kinase of the yeast "High Osmolarity Glycerol" (HOG) pathway, Hog1-GFP. By sequential treatment of the yeast cells with a selective Hog1 kinase inhibitor and sorbitol, the subcellular localization of Hog1-GFP was analysed on a single-cell level. The results showed impaired Hog1-GFP nuclear localization, providing evidence of a congenial design. The setup made it possible to remove and add an agent within 2 seconds, which is valuable for investigating the dynamic signal transduction pathways and cannot be done using traditional methods. We are confident that the features of the four-inlet microfluidic system will be a valuable tool and hence contribute significantly to unravel the mechanisms of the HOG pathway and similar dynamic signal transduction pathways.
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| 43. |
- Henriksson, Jens, 1991, et al.
(författare)
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Towards Structured Evaluation of Deep Neural Network Supervisors
- 2019
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Ingår i: Proceedings - 2019 IEEE International Conference on Artificial Intelligence Testing, AITest 2019. - New York : Institute of Electrical and Electronics Engineers Inc.. - 9781728104928 ; 1
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Konferensbidrag (refereegranskat)abstract
- Deep Neural Networks (DNN) have improved the quality of several non-safety related products in the past years. However, before DNNs should be deployed to safety-critical applications, their robustness needs to be systematically analyzed. A common challenge for DNNs occurs when input is dissimilar to the training set, which might lead to high confidence predictions despite proper knowledge of the input. Several previous studies have proposed to complement DNNs with a supervisor that detects when inputs are outside the scope of the network. Most of these supervisors, however, are developed and tested for a selected scenario using a specific performance metric. In this work, we emphasize the need to assess and compare the performance of supervisors in a structured way. We present a framework constituted by four datasets organized in six test cases combined with seven evaluation metrics. The test cases provide varying complexity and include data from publicly available sources as well as a novel dataset consisting of images from simulated driving scenarios. The latter we plan to make publicly available. Our framework can be used to support DNN supervisor evaluation, which in turn could be used to motive development, validation, and deployment of DNNs in safety-critical applications.
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| 44. |
- Lundin, Johan, 1975, et al.
(författare)
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The Illusion of Structure : About Harmonization and Variation in Competence Management System Practices in a Public Healthcare Organization
- 2015
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Ingår i: ECIS 2015 Completed Research Papers. - Münster : ECIS. - 9783000502842 ; , s. 1-14
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Konferensbidrag (refereegranskat)abstract
- This paper reports on a study of the use of a competence management system in a public healthcare organization. Even though systems for documenting and managing competence information have been implemented widely in most sectors, there is a lack of research focusing the adoption and use of such systems in general, and in particular within the public sector. The use of the system was studied through interviews, observations as well as document studies. In our analysis, we focus on local adap- tation practices, and variations in use, as well as how this functionality is carried by social or materi- al parts of the system. By so doing, we show how contradictory perspectives of the system's purpose and use is present in the organization, and surprisingly unproblematic. We argue that our in-depth case analysis illustrates how efforts of standardization in a system benignly can co-exist with local adaptation and variation.
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| 45. |
- Löfhede, Johan, et al.
(författare)
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Comparing a Supervised and an Unsupervised Classification Method for Burst Detection in Neonatal EEG
- 2008
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Ingår i: Proceedings of Engineering in Medicine and Biology Society, EMBS 2008. 30th Annual International Conference of the IEEE, 20-24 August, 2008. - : IEEE. - 1557-170X. - 9781424418145 ; , s. 3836-3839
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Konferensbidrag (refereegranskat)abstract
- Hidden Markov Models (HMM) and Support Vector Machines (SVM) using unsupervised and supervised training, respectively, were compared with respect to their ability to correctly classify burst and suppression in neonatal EEG. Each classifier was fed five feature signals extracted from EEG signals from six full term infants who had suffered from perinatal asphyxia. Visual inspection of the EEG by an experienced electroencephalographer was used as the gold standard when training the SVM, and for evaluating the performance of both methods. The results are presented as receiver operating characteristic (ROC) curves and quantified by the area under the curve (AUC). Our study show that the SVM and the HMM exhibit similar performance, despite their fundamental differences.
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| 46. |
- Steghöfer, Jan-Philipp, 1983, et al.
(författare)
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Teaching Agile : Addressing the conflict between project delivery and application of Agile methods
- 2016
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Ingår i: Proceedings - International Conference on Software Engineering. - New York, NY, USA : IEEE Computer Society. - 0270-5257. - 9781450341615 - 9781450342056 ; , s. 303-312
-
Konferensbidrag (refereegranskat)abstract
- This paper analyses the changes we have made in teaching agile methodologies, practices, and principles in four courses in order to address a specific dilemma: students need to apply agile methods in order to learn them, but when complementing our courses with applied content, we face the problem that students perceive the learning and application of agile methods as less important than delivering a finished product at the end of the course. This causes students to not apply theoretical process knowledge and therefore to not develop necessary skills associated with working with defined processes in the industry. Concretely, we report on our experience with teaching Scrum with Lego, removing formal grading requirements on the delivered product, emphasising process application in post-mortem reports, and organisational changes to support the process during supervision. These changes are analysed in the context of student satisfaction, teacher observations, and achievements of learning outcomes. We also provide an overview of the lessons learnt to help guide the design of courses on agile methodologies.
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| 47. |
- Brandström, Per, 1959, et al.
(författare)
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The Swedish Reflux Trial in Children: I. Study Design and Study Population Characteristics
- 2010
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Ingår i: Journal of Urology. - : Ovid Technologies (Wolters Kluwer Health). - 0022-5347 .- 1527-3792. ; 184:1, s. 274-279
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Konferensbidrag (refereegranskat)abstract
- Purpose: We compared the rates of febrile urinary tract infection, kidney damage and reflux resolution in children with vesicoureteral reflux treated in 3 ways, including antibiotic prophylaxis, endoscopic therapy and surveillance with antibiotics only for symptomatic urinary tract infection. Materials and Methods: Children 1 to younger than 2 years with grade reflux were recruited into this prospective, open, randomized, controlled, multi-center study and followed for 2 years after randomization. The main study end points were recurrent febrile urinary tract infection, renal status on dimercaptosuccinic acid scintigraphy and reflux status. Outcomes were analyzed by the intent to treat principle. Results: During a 6-year period 128 girls and 75 boys entered the study. In 96% of cases reflux was detected after urinary tract infection. The randomization procedure was successful and resulted in 3 groups matched for relevant factors. Recruitment was slower than anticipated but after patients were entered adherence to the protocol was good. Of the children 93% were followed for the intended 2 years without a treatment arm change. All except 2 patients completed 2-year followup scintigraphy. Conclusions: Recruitment was difficult but a substantial number of children were entered and randomly assigned to 3 groups with similar basic characteristics. Good adherence to the protocol made it possible to address the central study questions.
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| 48. |
- Thomas, Richard D., et al.
(författare)
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DESIREE : Physics with cold stored ion beams
- 2015
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Ingår i: DR2013. - : EDP Sciences. ; 84, s. 01004-01004
-
Konferensbidrag (refereegranskat)abstract
- Here we will briefly describe the commissioning of the Double ElectroStatic Ion Ring ExpEriment (DESIREE) facility at Stockholm University, Sweden. This device uses purely electrostatic focussing and deflection elements and allows ion beams of opposite charge to be confined under extreme high vacuum and cryogenic conditions in separate rings and then merged over a common straight section. This apparatus allows for studies of interactions between cations and anions at very low and well-defined centre-of-mass energies (down to a few meV) and at very low internal temperatures (down to a few K).
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| 49. |
- Asadzadeh, Mohammad, 1952, et al.
(författare)
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A combined discontinuous Galerkin and finite volume scheme for multi-dimensional VPFP system
- 2011
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Ingår i: AIP Conference Proceedings. 27th International Symposium on Rarefied Gas Dynamics, RGD27; Pacific Grove, CA; United States; 10 July 2011 through 15 July 2011. - : AIP. - 0094-243X .- 1551-7616. - 9780735408890 ; 1333:Part 1, s. 57-62, s. 57-62
-
Konferensbidrag (refereegranskat)abstract
- We construct a numerical scheme for the multi-dimensional Vlasov-Poisson-Fokker-Planck system based on a combined finite volume (FV) method for the Poisson equation in spatial domain and the streamline diffusion (SD) and discontinuous Galerkin (DG) finite element in time, phase-space variables for the Vlasov-Fokker-Planck equation.
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| 50. |
- Bartoszek, Krzysztof, 1984-
(författare)
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The Laplace Motion in Phylogenetic Comparative Methods
- 2012
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Ingår i: Proceedings of the Eightteenth National Conference on Applications of Mathematics in Biology and Medicine. - 9788373484344 ; , s. 25-30
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Konferensbidrag (refereegranskat)abstract
- The majority of current phylogenetic comparative methods assume that the stochastic evolutionary process is homogeneous over the phylogeny or offer relaxations of this in rather limited and usually parameter expensive ways. Here we make a preliminary investigation, by means of a numerical experiment, whether the Laplace motion process can offer an alternative approach.
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