TY - JOUR A1 - Geisbauer, Christian A1 - Wöhrl, Katharina A1 - Mittmann, Christoph A1 - Schweiger, Hans-Georg T1 - Review of Safety Aspects of Calendar Aged Lithium Ion Batteries JF - Journal of the Electrochemical Society N2 - Nowadays, lithium ion batteries have found their place in a various field of portable applications. With the upcoming of electrically propelled vehicles, it is mandatory to guarantee a safe and predictable behavior during the whole lifetime and not only after manufacturing during performance tests. To gain a general overview of the abuse behavior, research on the topic of abusive tests on calendar-aged cells is being investigated, split up depending on the electrode composition and lined up against each other. It can be shown, that almost all abuse experiments have been performed with external heating tests in the past, still leaving research gaps that need to be filled. UR - https://doi.org/10.1149/1945-7111/ab89bf Y1 - 2020 UR - https://doi.org/10.1149/1945-7111/ab89bf UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-10183 SN - 1945-7111 VL - 167 IS - 9 PB - IOP Publishing CY - Bristol ER - TY - JOUR A1 - Böhm, Klaus A1 - Kubjatko, Tibor A1 - Paula, Daniel A1 - Schweiger, Hans-Georg T1 - New developments on EDR (Event Data Recorder) for automated vehicles JF - Open Engineering N2 - With the upcoming new legislative rules in the EU on Event Data Recorder beginning 2022 the question is whether the discussed data base is sufficient for the needs of clarifying accidents involving automated vehicles. Based on the reconstruction of real accidents including vehicles with ADAS combined with specially designed crash tests a broader data base than US EDR regulation (NHTSA 49 CFR Part 563.7) is proposed. The working group AHEAD, to which the authors contribute, has already elaborated a data model that fits the needs of automated driving. The structure of this data model is shown. Moreover, the special benefits of storing internal video or photo feeds form the vehicle camera systems combined with object data is illustrated. When using a sophisticate 3D measurement method of the accident scene the videos or photos can also serve as a control instance for the stored vehicle data. The AHEAD Data Model enhanced with the storage of the video and photo feeds should be considered in the planned roadmap of the Informal Working Group (IWG) on EDR/ DSSAD (Data Storage System for Automated Driving) reporting to UNECE WP29. Also, a data access over the air using technology already applied in China for electric vehicles called Real Time Monitoring would allow a quantum leap in forensic accident reconstruction. UR - https://doi.org/10.1515/eng-2020-0007 KW - Event Data Recorder (EDR) KW - automated vehicles KW - video and photo feeds KW - Real Time Monitoring (RTM) KW - AHEAD (Aggregated Homologation proposal for Event data recorder for Automated Driving) Y1 - 2020 UR - https://doi.org/10.1515/eng-2020-0007 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9263 SN - 2391-5439 VL - 10 IS - 1 SP - 140 EP - 146 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Steger, Fabian A1 - Nitsche, Alexander A1 - Arbesmeier, Alexander A1 - Brade, Katja A1 - Schweiger, Hans-Georg A1 - Belski, Iouri T1 - Teaching Battery Basics in Laboratories: Hands-On Versus Simulated Experiments JF - IEEE Transactions on Education N2 - Contribution: Prior studies comparing the effectiveness of different laboratory learning modes do not allow one to draw a universally valid conclusion, as other influences are mixed with the learning modes. In order to contribute to the existing body of work and to add another piece to the puzzle, this article demonstrates an improved methodology to evaluate the effectiveness of computer-simulated laboratories in comparison to hands-on exercises using a battery basics practical course as a case study. Background: Computer-simulated experiments are becoming increasingly popular for conducting laboratory exercises in higher education and vocational training institutions. To ensure the consistent quality of laboratory learning, an accurate comparison between the results of simulated experiments and practical hands-on experiments is required. Intended Outcomes: In this article, the achievement of the following learning objectives were compared between the two laboratory modes: 1) comprehension of the most important parameters of battery cells and 2) knowledge on how these parameters can be determined using adequate experimental procedures. Application Design: To avoid interference of factors other than laboratory mode on the learning, laboratory instructions and experimental interfaces ensured identical execution of the experiments in the compared modes. Using a counterbalanced methodology, the two laboratory modes alternated by the session, while the experimental procedures remained constant regardless of the respective modes. Findings: Tests taken by the participants after conducting the laboratory experiments revealed that hands-on laboratories resulted in statistically significantly better student performance than simulated laboratories. This difference was even more pronounced for the participants that finished a vocational education and training program before the university studies. UR - https://doi.org/10.1109/TE.2020.2970554 KW - battery KW - electrical engineering KW - energy storages KW - hands-on KW - knowledge gain KW - laboratory learning KW - simulation KW - student experience Y1 - 2020 UR - https://doi.org/10.1109/TE.2020.2970554 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9517 SN - 1557-9638 VL - 63 IS - 3 SP - 198 EP - 208 PB - IEEE CY - Piscataway ER - TY - JOUR A1 - Kim, Woong-Ki A1 - Steger, Fabian A1 - Kotak, Bhavya A1 - Knudsen, Peter V. R. A1 - Girgsdies, Uwe A1 - Schweiger, Hans-Georg T1 - Water Condensation in Traction Battery Systems JF - Energies N2 - Lithium-ion traction battery systems of hybrid and electric vehicles must have a high level of durability and reliability like all other components and systems of a vehicle. Battery systems get heated while in the application. To ensure the desired life span and performance, most systems are equipped with a cooling system. The changing environmental condition in daily use may cause water condensation in the housing of the battery system. In this study, three system designs were investigated, to compare different solutions to deal with pressure differences and condensation: (1) a sealed battery system, (2) an open system and (3) a battery system equipped with a pressure compensation element (PCE). These three designs were tested under two conditions: (a) in normal operation and (b) in a maximum humidity scenario. The amount of the condensation in the housing was determined through a change in relative humidity of air inside the housing. Through PCE and available spacing of the housing, moisture entered into the housing during the cooling process. While applying the test scenarios, the gradient-based drift of the moisture into the housing contributed maximum towards the condensation. Condensation occurred on the internal surface for all the three design variants. UR - https://doi.org/10.3390/en12061171 KW - traction battery system KW - condensation KW - durability test KW - pressure compensation element KW - behavior of an enclosed system Y1 - 2019 UR - https://doi.org/10.3390/en12061171 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9560 SN - 1996-1073 VL - 12 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Notomista, Gennaro A1 - Botsch, Michael T1 - A Machine Learning Approach for the Segmentation of Driving Maneuvers and its Application in Autonomous Parking JF - Journal of Artificial Intelligence and Soft Computing Research (JAISCR) N2 - A classification system for the segmentation of driving maneuvers and its validation in autonomous parking using a small-scale vehicle are presented in this work. The classifiers are designed to detect points that are crucial for the path-planning task, thus enabling the implementation of efficient autonomous parking maneuvers. The training data set is generated by simulations using appropriate vehicle–dynamics models and the resulting classifiers are validated with the small-scale autonomous vehicle. To achieve both a high classification performance and a classification system that can be implemented on a microcontroller with limited computational resources, a two-stage design process is applied. In a first step an ensemble classifier, the Random Forest (RF) algorithm, is constructed and based on the RF-kernel a General Radial Basis Function (GRBF) classifier is generated. The GRBF-classifier is integrated into the small-scale autonomous vehicle leading to excellent performance in parallel-, cross- and oblique- parking maneuvers. The work shows that segmentation using classifies and open-loop control are an efficient approach in autonomous driving for the implementation of driving maneuvers. UR - https://doi.org/10.1515/jaiscr-2017-0017 KW - autonomous parking KW - ensemble learning KW - maneuver segmentation Y1 - 2017 UR - https://doi.org/10.1515/jaiscr-2017-0017 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9604 SN - 2449-6499 VL - 7 IS - 4 SP - 243 EP - 255 PB - De Gruyter Open CY - Warschau ER - TY - JOUR A1 - Sequeira, Gerald Joy A1 - Patel, Akshay A1 - Afraj, Shahabaz A1 - Lugner, Robert A1 - Brandmeier, Thomas T1 - FEM-based methodology for crash severity estimation in frontal crash scenarios JF - IOP Conference Series: Materials Science and Engineering N2 - With the technological development of forward-looking sensors, researchers are exploring their use not only for advanced driver assistance systems but also to gain important pre-crash information. Based on this pre-crash information, if the occupant motion inside the vehicle structure can be predicted for the oncoming crash scenario, then an optimal restraint strategy can be planned before the crash. This paper introduces a two-step FEM simulation based methodology for predicting the occupant severity in head-on crash scenarios. In the first step, we simulate the vehicle level model with different impact positions and relative approach angles. The results of these simulations, linear velocities in the longitudinal and lateral direction and angular velocities (roll, pitch, and yaw) during in-crash phase are the loading conditions for next simulation step (occupant level). This step simulates the motion of the driver in different crash scenarios. In this paper, we investigate the head, neck, and chest injury risks from vehicle-to-vehicle crash both traveling at 50 kilometers per hour. Prediction of the head injury criterion, identifying the cases where additional deployment of side-airbags and discussion of injury criteria with contour plots are the main outcome of this paper. UR - https://doi.org/10.1088/1757-899X/831/1/012019 Y1 - 2020 UR - https://doi.org/10.1088/1757-899X/831/1/012019 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-13159 SN - 1757-899X SN - 1757-8981 VL - 2020 IS - 831 PB - IOP CY - Bristol ER - TY - JOUR A1 - Weigl, Klemens A1 - Ponocny, Ivo T1 - Group sequential designs applied in psychological research JF - Methodology: European Journal of Research Methods for the Behavioral and Social Sciences N2 - Psychological research is confronted with ever-increasing demands to save resources such as time and money while assuring high ethical standards. In medical and pharmaceutical research, group sequential designs have fundamentally changed traditional statistical testing approaches featuring only one analysis at the end of a single-stage study. They enable early stopping at an interim stage, after a group of observations, for efficacy or futility in case of an overwhelmingly large or small effect, respectively. Otherwise, the trial is continued to the next stage. On average over many studies time and money are saved and more ethical trials are facilitated by diminishing the risk of patients' exposure to inferior treatments. We provide an easy-to-use tutorial for psychological research replete with easily understandable figures highlighting the core idea of different group sequential designs, a workflow chart, an empirical real-world data set, and the annotated R code. Finally, we demonstrate the application of early stopping for efficacy. UR - https://doi.org/10.5964/meth.2811 KW - group sequential designs KW - interim analyses KW - workflow chart KW - R Code KW - tutorial Y1 - 2020 UR - https://doi.org/10.5964/meth.2811 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-13190 SN - 1614-2241 VL - 16 IS - 1 SP - 75 EP - 91 PB - PsychOpen CY - Trier ER - TY - CHAP A1 - de Meer, Jan A1 - Waedt, Karl A1 - Rennoch, Axel A1 - Hof, Hans-Joachim T1 - 4th GI/ACM Workshop on standardization of I4.0 automation and control systems T2 - Lecture Notes in Informatics (LNI) - Proceedings UR - https://doi.org/10.18420/inf2019_ws27 Y1 - 2019 UR - https://doi.org/10.18420/inf2019_ws27 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-17752 SN - 978-3-88579-689-3 SN - 1617-5468 VL - 2019 IS - Volume P-295 SP - 241 EP - 242 PB - Gesellschaft für Informatik CY - Bonn ER - TY - JOUR A1 - Kundinger, Thomas A1 - Sofra, Nikoletta A1 - Riener, Andreas T1 - Assessment of the Potential of Wrist-Worn Wearable Sensors for Driver Drowsiness Detection JF - Sensors N2 - Drowsy driving imposes a high safety risk. Current systems often use driving behavior parameters for driver drowsiness detection. The continuous driving automation reduces the availability of these parameters, therefore reducing the scope of such methods. Especially, techniques that include physiological measurements seem to be a promising alternative. However, in a dynamic environment such as driving, only non- or minimal intrusive methods are accepted, and vibrations from the roadbed could lead to degraded sensor technology. This work contributes to driver drowsiness detection with a machine learning approach applied solely to physiological data collected from a non-intrusive retrofittable system in the form of a wrist-worn wearable sensor. To check accuracy and feasibility, results are compared with reference data from a medical-grade ECG device. A user study with 30 participants in a high-fidelity driving simulator was conducted. Several machine learning algorithms for binary classification were applied in user-dependent and independent tests. Results provide evidence that the non-intrusive setting achieves a similar accuracy as compared to the medical-grade device, and high accuracies (>92%) could be achieved, especially in a user-dependent scenario. The proposed approach offers new possibilities for human–machine interaction in a car and especially for driver state monitoring in the field of automated driving. UR - https://doi.org/10.3390/s20041029 KW - drowsiness detection KW - driver state KW - simulator study KW - physiological measures KW - machine learning KW - wearable sensors KW - automated driving Y1 - 2020 UR - https://doi.org/10.3390/s20041029 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9506 SN - 1424-8220 VL - 20 IS - 4 PB - MDPI CY - Basel ER - TY - JOUR A1 - Riener, Andreas A1 - Jeon, Myounghoon T1 - Guest editors’ introduction: multimodal technologies and interaction in the era of automated driving JF - Multimodal Technologies and Interaction UR - https://doi.org/10.3390/mti3020041 Y1 - 2019 UR - https://doi.org/10.3390/mti3020041 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-13339 SN - 2414-4088 VL - 3 IS - 2 PB - MDPI CY - Basel ER - TY - CHAP A1 - Steger, Fabian A1 - Nitsche, Alexander A1 - Miley, Cayler A1 - Schweiger, Hans-Georg A1 - Belski, Iouri ED - Huda, Nazmul ED - Inglis, David ED - Tse, Nicholas ED - Town, Graham T1 - Laboratory Learning: Hands-on versus Simulated Experiments T2 - Proceedings of the 28th Annual Conference of the Australasian Association for Engineering Education (AAEE 2017) N2 - CONTEXT Many universities and vocational training institutions conduct laboratories as simulated experiments. This is due to the costs and supervision needs to conduct hands-on labs safely. Numerous studies have presented mixed opinions on whether hands-on laboratory work is more conducive to learning than a simulated laboratory. Most of the studies put students from experimental and control groups in significantly different conditions. Therefore, it is hard to reach any definite conclusion regarding the influence of the learning mode onto the learning achievements. PURPOSE This study compares learning outcomes of student laboratory work in an energy storages course conducted in two different modes: first as a practical hands-on exercise and second using computer-based simulations. APPROACH In order to provide reliable insights, this study implements optimized research methodology to avoid any other effect (e.g. learning synchronicity/distance learning/instructions) on the learning outcome rather than the effect of the learning mode itself. The student laboratory experiments were created in a manner that they could be conducted in both modes in the same way and using a single set of instructions. To ensure a comparable group environment for the individual student, the students were arranged into two similar groups based on the student's practical experience. In this crossover study, the groups were taught the same topics by means of interchanging learning modes. RESULTS To evaluate the influence of each mode on student learning, short written tests regarding the previous experiment were conducted at the beginning of the subsequent laboratory session. 102 students have taken part in the study in two years. Overall learning results of hands-on experiments were slightly better than those of simulated laboratories (Cohen's d=0.25), the difference in performance was statistically significant (p<0.02). Through solicited feedback on each laboratory session, in hands-on mode more students expressed they have acquired new insights/comprehensions (76% vs. 66%, Cohen's d=0.23, small effect, p<0.07). CONCLUSIONS Following the strategy not to optimize the lessons individually to the learning mode, other influences on the learning outcome, which were usually mixed, were excluded. The students' subjective opinions show advantages of the hands-on mode. Based on the objective data, a weak, but significant outcome to better knowledge acquisition with hands-on laboratory experiments was achieved. This observation is against the trend of the literature in the last years towards better or equal learning with nontraditional labs. Some of the excluded factors might have a stronger influence on student learning than estimated previously. To get a clear view, the authors recommend isolated research. KW - Hands-on vs. simulated experiment KW - battery experiment KW - learning-mode comparison Y1 - 2017 UR - https://researchers.mq.edu.au/en/publications/proceedings-of-the-28th-annual-conference-of-the-australasian-ass UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-15581 SN - 978-0-646-98026-3 SP - 940 EP - 947 PB - Macquarie University CY - Sydney ER -