TY - JOUR A1 - Koder, Alexander A1 - Schwanzer, Peter A1 - Zacherl, Florian A1 - Rabl, Hans-Peter A1 - Mayer, Wolfgang A1 - Gruber, Georg A1 - Dotzer, Thomas T1 - Combustion and emission characteristics of a 2.2L common-rail diesel engine fueled with jatropha oil, soybean oil, and diesel fuel at various EGR-rates JF - Fuel N2 - To investigate the combustion and emission behavior of straight vegetable oils (SVO), jatropha oil, soybean oil, and diesel fuel were tested. For this research, a 2.2L common-rail engine with a two-stage turbocharging concept was equipped with a cylinder pressure indication system, an exhaust-gas analyzer, an AVL Micro Soot sensor and a Scanning Mobility Particle Sizer 3936 (SMPS) device to detect the particle-size-distribution (PSD). At a low and mid-load engine-operating point (EOP), the thermodynamic and emissions were investigated under various exhaust gas recirculation (EGR) rates with respect to the PSD. Moreover, the injection behavior of the three test fuels was analyzed separately using an injection rate analyzer. This procedure facilitates the thermodynamic investigations of the engine process and allows the calculation of the hydraulic delay (HD) as well as the ignition delay (ID). The ID of the SVO fuels compared to diesel fuel was found to be lower at all engine-operating modes, while jatropha oil always showed the shortest ID. In the particulate-nitrogen oxide (NOX) trade-off, the SVO fuels showed higher particulate matter (PM) emissions at the low-load EOP, whereas the PM emissions of diesel fuel overtop the SVO fuels at a higher engine load. With increased EGR-rates, a rise in the particle size was observed for all fuels. At the low-load EOP, the SVO fuels showed larger particles for high EGR-rates. This effect also changed by increasing the engine-load to the mid-load EOP, wherein the particle size of the diesel fuel emissions is higher by applying elevated EGR-rates. KW - BEHAVIOR KW - BLENDS KW - Exhaust gas recirculation KW - IGNITION KW - INJECTION KW - Jatropha oil KW - KARANJA KW - Particle-size-distribution KW - PERFORMANCE KW - RME KW - Soybean oil KW - Straight vegetable oil combustion KW - VEGETABLE-OILS Y1 - 2018 U6 - https://doi.org/10.1016/j.fuel.2018.04.147 VL - 228 IS - September SP - 23 EP - 29 PB - Elsevier ER - TY - CHAP A1 - Koder, Alexander A1 - Zacherl, Florian A1 - Rabl, Hans-Peter A1 - Mayer, Wolfgang A1 - Gruber, Georg A1 - Dotzer, Thomas T1 - Jatropha Oil as an Alternative Fuel for Modern Diesel Engines - Injection Characteristics and EGR-Compatibility T2 - WCX 17: SAE World Congress 2017 N2 - An effective way to reduce greenhouse gas emissions (GHGs) is to use rurally produced straight jatropha oil as a substitute for diesel fuel. However, the different physical and chemical properties of straight vegetable oils (SVOs) require a customized setup of the combustion engine, particularly of the injection timing and quantity. Therefore, this study demonstrates the differences in the injection and combustion processes of jatropha oil compared to diesel fuel, particularly in terms of its compatibility with exhaust gas recirculation (EGR). A 2.2 l common-rail diesel engine with a two-stage turbocharging concept was used for testing. To examine the differences in injection rate shaping of diesel fuel and jatropha oil, the injector was tested with an injection rate analyzer using both the fuels. To investigate the combustion process, the engine was mounted at an engine test bench and equipped with a cylinder pressure indication system. All limited emissions, as well as fuel consumption, were measured. Various injection strategies, boost and rail pressure levels were tested at different EGR rates in terms of their impact on the combustion process. EGR in particular offers a great potential in the case of jatropha oil combustion due to its oxygen content. In addition, the investigation of injection rate shaping in combination with cylinder pressure analysis allowed a detailed thermodynamic evaluation of the combustion process. Ignition delay (ID) was also analyzed using a new method to calculate the start of combustion (SOC) Y1 - 2017 U6 - https://doi.org/10.4271/2017-01-5000 PB - SAE International ER - TY - GEN A1 - Hauser, Florian A1 - Reuter, Rebecca A1 - Gegenfurtner, Andreas A1 - Gruber, Hans A1 - Mottok, Jürgen A1 - Hutzler, Ivonne T1 - Heuristics in Software Modelling: An Eyetracking Study T2 - Earli Book of Abstracts N2 - To investigate the role of heuristics in the domain of software engineering, an eye tracking study was conducted in which experts and novices were compared. The study focused on one of the most challenging parts in this domain: the generation of an object model for a software product based on a requirements specification. During their training, software engineers are taught different techniques to solve this task. One of these techniques is the noun/verb analysis. However, it is still unclear to what extent novice and expert programmers are making use of it. Ideally, the noun/verb analysis works as a heuristic and helps programmers to make fast and accurate decisions. Participants in the study were 40 software programmers at four levels of expertise (novices, intermediates, experienced rogrammers, experts). They were presented with ten decision tasks. In each task, participants read a requirement specification and then had to choose one out of three presented class diagrams that they considered the best solution. During the task, their eye movements were recorded. Results show that all participants used the noun/verb analysis as a heuristic. Programmers with higher levels of expertise, however, outperformed programmers with lower levels of expertise. Interestingly, the more experienced programmers were not following the noun/verb analysis in a blindfolded way. They realised that the noun/verb analysis would produce diagrams, but a skilled software architect would not model them in this way. Instead they created their models in a way that they perceived as more logical and realistic Y1 - 2019 UR - https://earli.org/sites/default/files/2019-09/BOA-2019.pdf PB - RWTH Aachen ER - TY - CHAP A1 - Gruber, Hans A1 - Wolff, Christian A1 - Mottok, Jürgen A1 - Bazo, Alexander A1 - Hauser, Florian A1 - Schreistetter, Stefan T1 - Tutorial on Software Engineering Education in Co-Located Multi-User Eye-Tracking-Environments T2 - Proceedings of the 32nd IEEE Conference on Software Engineering Education and Training: Munich, November 2020 N2 - We briefly describe a tutorial on the application of Eye-Tracking technology for Software Engineering Education. We will showcase our setup of a large-scale Eye-Tracking-Classroom and its usage for real-time improvement of traditional learning scenarios in Software Engineering Education. We will focus on the integration of gaze data into modern integrated development environments (IDEs) and demonstrate a complete workflow for its usage in co-located multi-user Eye-Tracking-Environments. KW - eye-tracking KW - software engineering education KW - multi-user eye tracking KW - real-time learning scenarios Y1 - 2020 U6 - https://doi.org/10.1109/CSEET49119.2020.9206170 ER - TY - CHAP A1 - Hauser, Florian A1 - Schreistetter, Stefan A1 - Reuter, Rebecca A1 - Mottok, Jürgen A1 - Gruber, Hans A1 - Holmqvist, Kenneth A1 - Schorr, Nick T1 - Code reviews in C++: Preliminary results from an eye tracking study T2 - ETRA '20 Short Papers: ACM Symposium on Eye Tracking Research and ApplicationsJune 2020 N2 - Code reviews are an essential part of quality assurance in modern software projects. But despite their great importance, they are still carried out in a way that relies on human skills and decisions. During the last decade, there have been several publications on code reviews using eye tracking as a method, but only a few studies have focused on the performance differences between experts and novices. To get a deeper understanding of these differences, the following experiment was developed: This study surveys expertise-related differences in experts’, advanced programmers’, and novices’ eye movements during the review of eight short C++ code examples, including correct and erroneous codes. A sample of 35 participants (21 novices, 14 advanced and expert programmers) were recruited. A Tobii Spectrum 600 was used for the data collection. Measures included participants’ eye movements during the code review, demographic background data, and cued retrospective verbal comments on replays of their own eye movement recordings. Preliminary results give proof for experience-related differences between participants. Advanced and expert programmers performed significantly better in case of error detection and the eye tracking data implies a more efficient reviewing strategy. Y1 - 2020 SN - ISBN 9781450371346 U6 - https://doi.org/10.1145/3379156.3391980 SP - 1 EP - 5 ER - TY - CHAP A1 - Hauser, Florian A1 - Stark, Theresa A1 - Mottok, Jürgen A1 - Gruber, Hans A1 - Reuter, Rebecca T1 - Deliberate Practice in Programming: How is it carried out by programmers? T2 - ECSEE '20: Proceedings of the 4th European Conference on Software Engineering Education, Seeon, Germany, June 2020 N2 - This work in progress study examines through which activities programmers perform deliberate practice to improve their own skills in coding and programming. For this reason, a qualitative questionnaire was developed and conducted with a sample of 22 participants. The results indicate that programmers perform formal and informal forms of training and learning. Typically, a classical programming training in the context of a university course or for work-related reasons is a first step in the acquisition of expertise. Building on these basic skills, non-formal and informal learning activities are carried out by the learners. Especially the social interaction and the collaborative work with other programmers is of great importance in this context. The activities mentioned by the test persons fulfil the characteristics of deliberate practice and will be examined more closely in a further study. Y1 - 2020 SN - ISBN 9781450377522 U6 - https://doi.org/10.1145/3396802.3396815 SP - 42 EP - 46 ER - TY - CHAP A1 - Hauser, Florian A1 - Reuter, Rebecca A1 - Gegenfurtner, Andreas A1 - Gruber, Hans A1 - Mottok, Jürgen T1 - Eye movements in software modelling – what do they tell us about heuristics T2 - 12th International Conference of Education, Research and Innovation (ICERI 2019), Conference Proceedings, 2019, Seville (Spain) Y1 - 2019 SN - 978-84-09-14755-7 U6 - https://doi.org/10.21125/iceri.2019.1469 SP - 6064 EP - 6070 ER - TY - CHAP A1 - Nivala, Markus A1 - Hauser, Florian A1 - Mottok, Jürgen A1 - Gruber, Hans T1 - Developing visual expertise in software engineering: An eye tracking study T2 - IEEE Global Engineering Education Conference (EDUCON), 10-13 April 2016, Abu Dhabi, UAE N2 - Program comprehension and the ability to find program errors are key skills of software engineering. The aim of this pilot study was to examine the visual processes of novice and advanced programmers in authentic tasks. Fifteen novices and eight advanced programmers were given eight short pieces of code. Their task was to either identify an error or give the output of the code. Eye movements and keyboard activity were recorded. On average, the novices spent more time reading the code than composing the response, whereas the more advanced programmers started composing the response sooner and spent more time on it. In general, the advanced programmers had shorter fixations and saccades. The results suggest that the advanced programmers are quicker to grasp the essence of the code and able to see more details in it. The advanced programmers had shorter fixations and saccade lengths during the second phase which might indicate the process of chunking. KW - program comprehension KW - debugging KW - software engineering KW - visual expertise KW - eye tracking Y1 - 2016 U6 - https://doi.org/10.1109/EDUCON.2016.7474614 SP - 613 EP - 620 ER - TY - CHAP A1 - Hauser, Florian A1 - Reiß, Markus A1 - Nivala, Markus A1 - Mottok, Jürgen A1 - Gruber, Hans T1 - Eye tracking applied: Visual expertise in code reviews T2 - 9th International Conference on Education and New Learning Technologies, EDULEARN17, 3-5 July, 2017, Barcelona, Spain, Proceedings Y1 - 2017 U6 - https://doi.org/10.21125/edulearn.2017.1084 SP - 379 EP - 389 ER - TY - CHAP A1 - Nivala, Markus A1 - Hauser, Florian A1 - Jossberger, Helen A1 - Reiß, Markus A1 - Mottok, Jürgen A1 - Gruber, Hans T1 - Detecting errors in program flow diagrams: Comparing novices and advanced programmers T2 - EARLI Biennial Conference 2017, 17th European Association for Research on Learning and Instruction, 29 August - 2 September, 2017 - University of Tampere, Finland Y1 - 2017 ER - TY - CHAP A1 - Hauser, Florian A1 - Reuter, Rebecca A1 - Gruber, Hans A1 - Mottok, Jürgen T1 - Research competence: Modification of a questionnaire to measure research competence at universities of applied sciences T2 - IEEE Global Engineering Education Conference (EDUCON), 17-20 April 2018, Santa Cruz de Tenerife, Spain N2 - This paper deals with the validation and modification of the German questionnaire "F-Komp". In its original version, it was intended to measure university students' research competences. In the beginning of this study, there were only a few tools available which were reliable. For the purposes of this study, they were not suitable. At the same time, there was no validated version of the F-Komp available, which made the whole validation process for further usage necessary. This questionnaire is based on a structure, which consist of different skills and knowledge and is focused on measuring research competence in general. The validation and modification of the F-Komp is therefore the aim of our contribution as well as a revised version of the questionnaire. We proceeded an explorative factor and a reliability analysis to do a general evaluation of the tool. Some modifications were done in the questionnaire to make it more suitable to the requirements of technical oriented universities of applied sciences [5]. Our revised version is slightly longer and contains several items to gather data about the participants demographics. The modified questionnaire is based on a more appropriate factor structure. This structure is more practically oriented and pays attention to ethical issues. In future cases, this questionnaire will be used in research oriented courses to measure students' progress in acquiring the knowledge and methods which are necessary to perform as a scientist in different research areas. KW - research oriented teaching KW - research competence KW - competence model KW - modification of a questionnaire Y1 - 2018 U6 - https://doi.org/10.1109/EDUCON.2018.8363216 SP - 109 EP - 117 ER - TY - CHAP A1 - Hutzler, Ivonne A1 - Hauser, Florian A1 - Reuter, Rebecca A1 - Mottok, Jürgen A1 - Gruber, Hans T1 - Will the noun/verb analysis be used to generate class diagrams? An eye tracking study T2 - IATED, 11th International Conference of Education, Research and Innovation (ICERI 2018), 12-14 November 2018, Seville, Spain Y1 - 2018 U6 - https://doi.org/10.21125/iceri.2018.1103 SP - 505 EP - 514 ER - TY - CHAP A1 - Hauser, Florian A1 - Mottok, Jürgen A1 - Reuter, Rebecca A1 - Hutzler, Ivonne A1 - Gruber, Hans T1 - Eye movement patterns in software engineering – What differs the expert from the novice? T2 - IATED, 11th International Conference of Education, Research and Innovation (ICERI 2018), 12-14 November 2018, Seville, Spain Y1 - 2018 U6 - https://doi.org/10.21125/iceri.2018.1129 ER - TY - JOUR A1 - Gegenfurtner, Andreas A1 - Boucheix, Jean-Michel A1 - Gruber, Hans A1 - Hauser, Florian A1 - Lehtinen, Erno A1 - Lowe, Richard K. T1 - The gaze relational index as a measure of visual expertise JF - Journal of Expertise N2 - Eye tracking is a powerful technique that helps reveal how people process visual information. This paper discusses a novel metric for indicating expertise in visual information processing. Named the Gaze Relational Index (GRI), this metric is defined as the ratio of mean fixation duration to fixation count. Data from two eye-tracking studies of professional vision and visual expertise in using 3D dynamic medical visualizations are presented as cases to illustrate the suitability and additional benefits of the GRI. Calculated values of the GRI were higher for novices than for experts, and higher in non-representative, semi-familiar / unfamiliar task conditions than in domain-representative familiar tasks. These differences in GRI suggest that, compared to novices, experts engaged in more knowledge-driven, top-down processing that was characterized by quick, exploratory visual search. We discuss future research aiming to replicate the GRI in professional domains with complex visual stimuli and to identify the moderating role of cognitive ability on GRI estimates. KW - eye tracking KW - fixations KW - information processing KW - professional vision KW - visual expertise Y1 - 2020 UR - https://www.journalofexpertise.org/articles/volume3_issue1/JoE_3_1_Gegenfurtner.pdf SN - 2573-2773 VL - 3 IS - March SP - 32 EP - 40 PB - Michigan State University ER - TY - CHAP A1 - Hauser, Florian A1 - Mottok, Jürgen A1 - Gruber, Hans ED - Mottok, Jürgen T1 - Eye Tracking Metrics in Software Engineering T2 - Proceedings of the 3rd European Conference of Software Engineering Education (ECSEE'18); Seeon/ Bavaria Germany, 14.06.2018 -15.06.2018 N2 - This paper aims to provide an overview of the interdisciplinary combination of educational science, psychology, software engineering and the eye tracking methodology. The domain of software engineering is offering great potential for applied eye tracking research and in turn it can benefit from the possibilities of this upcoming technology as well. Nevertheless, software engineering has to struggle with some obstacles. These are namely the different terms, missing guidelines for experimental setups and a lack of common and standardized metrics. If eye tracking should be used in a broader way these problems must be solved. The main purpose of this paper is to list all eye tracking metrics which are relevant for software engineering and to give guidelines to help beginners by avoiding possible pitfalls. Y1 - 2018 SN - 9781450363839 U6 - https://doi.org/10.1145/3209087.3209092 SP - 39 EP - 44 PB - ACM CY - New York, NY ER - TY - JOUR A1 - Schmidt, Simon A1 - Längler, Manuel A1 - Altenbuchner, Amelie A1 - Kobl, Louisa A1 - Gruber, Hans T1 - Acquiring the Art of Conducting: Deliberate Practice as Part of Professional Learning JF - Journal of Advanced Academics N2 - esearch was and still is involved in the controversial issue about innate talent or extensive practice as the determinants of excellent performance in a range of domains. This study aims to contribute by presenting an analysis of practice activities in a domain that appears to be particularly suitable—orchestral conducting. Most conductors usually attain expertise in instrument playing prior to commencing conducting studies. Twenty-seven students of German study programs of orchestral conducting (approximately 18.7% of the population) responded to a questionnaire about their practice activities in conducting programs and their instrumental experiences. Descriptive results show the wealth of prestudy experiences conducting students have. A clear influence on practice activities cannot be stated. During study, students rated conducting-specific practice activities as more demanding and devoted more time to them than to general music practice activities. Therefore, conducting-specific practice activities might have been practiced more deliberately than general music practice activities. KW - conducting KW - conservatory KW - deliberate practice KW - expertise KW - professional learning KW - talent development KW - university of music Y1 - 2021 U6 - https://doi.org/10.1177/1932202x21995931 VL - 32 IS - 3 SP - 354 EP - 379 PB - Sage ER - TY - CHAP A1 - Hauser, Florian A1 - Grabinger, Lisa A1 - Mottok, Jürgen A1 - Gruber, Hans T1 - Visual Expertise in Code Reviews: Using Holistic Models of Image Perception to Analyze and Interpret Eye Movements T2 - ETRA '23: 2023 Symposium on Eye Tracking Research and Applications, Tubingen Germany 30 May 2023- 2 June 2023 N2 - This study uses holistic models of image perception to analyze and interpret eye movements during a code review. 23 participants (15 novices and 8 experts) take part in the experiment. The subjects’ task is to review six short code examples in C programming language and identify possible errors. During the experiment, their eye movements are recorded by an SMI 250 REDmobile. Additional data is collected through questionnaires and retrospective interviews. The results implicate that holistic models of image perception provide a suitable theoretical background for the analysis and interpretation of eye movements during code reviews. The assumptions of these models are particularly evident for expert programmers. Their approach can be divided into different phases with characteristic eye movement patterns. It is best described as switching between scans of the code example (global viewing) and the detailed examination of errors (focal viewing). Y1 - 2023 U6 - https://doi.org/10.1145/3588015.3589189 SP - 1 EP - 7 PB - ACM ER - TY - CHAP A1 - Hauser, Florian A1 - Grabinger, Lisa A1 - Ezer, Timur A1 - Mottok, Jürgen A1 - Gruber, Hans ED - Gómez Chova, Luis ED - González Martínez, Chelo ED - Lees, Joanna T1 - Integrating deliberate practice in software engineering education T2 - ICERI 2024 Proceedings, 17th annual International Conference of Education, Research and Innovation,11-13 November, 2024, Seville, Spain Y1 - 2024 U6 - https://doi.org/10.21125/iceri.2024.1331 SP - 5457 EP - 5466 PB - IATED ER - TY - GEN A1 - Stark, T. A1 - Schreistetter, Stefan A1 - Reuter, Rebecca A1 - Hauser, Florian A1 - Holmqvist, Kenneth A1 - Mottok, Jürgen A1 - Gruber, Hans T1 - Learning from Gaze: Eye Movement Modeling Examples in Software Engineering Education T2 - Earli Book of Abstracts Y1 - 2021 UR - https://earli.org/assets/files/BOA-2021.pdf SP - 291 PB - Earli ER -