1. Railway bridge weigh-in-motion systemAleš Žnidarič, Jan Kalin, Maja Kreslin, Peter Favai, Przemyslaw Kolakowski, 2016, published scientific conference contribution Abstract: The paper provides an overview of the development of a railway bridge weigh-in-motion (B-WIM) system, one of the first of its kind for weighing trains in motion. A steel truss bridge in Poland was used for testing the system. Four trains which passed over the bridge were weighed in a rail yard in Warsaw. The conventional road B-WIM system was adapted to calculate the weights of the train carriages using the measured response from the test bridge and the accuracy of the system was assessed. Initial result showed that weights of one of the four trains of known weight were predicted very accurately, but accuracy of the other three trains was poor, with calculated carriage weights deviating by as much as 30% from their actual values. An in-depth analysis showed that these trains were changing velocity as they traversed the bridge and that the large errors were directly correlated to this changing velocity. The standard B-WIM algorithm, which assumed a constant velocity during the passage of a vehicle or train, was adjusted to allow for the effect of this changing velocity. The results improved dramatically, with the vast majority of the calculated wagon weights falling within 5% of their actual values. Further developments tailored the B-WIM algorithm for weighing trains, including the system interface that employs graphics of locomotives and wagons. The development of the railway B-WIM has been a success and has demonstrated that calculations of train weights using instrumented bridges can be efficiently performed.
Keywords: accuracy, B-WIM, measurement error, train, weigh-in-motion
Published in DiRROS: 05.09.2025; Views: 309; Downloads: 127
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2. Turning a point cloud into a Building Information Model (BIM) : defining and validating the accuracy requirements for existing buildingsKatja Žagar, Laurens Jozef Nicolaas Oostwegel, Katja Malovrh Rebec, 2025, published scientific conference contribution Abstract: Digitization of existing buildings is one of the main future goals, leading to efficient planning, renovation and maintenance. Among the existing buildings, a significant share is protected as a cultural heritage and their management is supervised because interventions on the protected sites are limited. Building information modeling (BIM) provides the opportunity to integrate accurate as-built information into the digital environment where it can easily be accessed and used. A digital representation of building creation usually starts with the acquisition of spatial data (point cloud), which is then used to create a semantically enriched model with certain geometric accuracy (BIM). In order for the model to serve its purpose, it is important to define how accurate the model should be. Since there are currently insufficient definitions of geometric requirementsfor specific BIM use cases, the research hypothesis was that the quality of BIM greatly depends on the modeler. The identified issue was approached with a study case. Using the point cloud of the existing building, the BIM was made and validated based on pre-defined accuracy requirements. Different accuracy validation methods were used in the process. Based on the results of the study case, conclusions and recommendations for efficient BIM creation were prepared.
Keywords: digitalization of existing buildings, point cloud, building information model, BIM, geometric accuracy
Published in DiRROS: 18.02.2025; Views: 831; Downloads: 450
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3. Evaluation of the training program for p16/ Ki-67 dual immunocytochemical staining interpretation for laboratory staff without experience in cervical cytology and immunocytochemistryVeronika Kloboves-Prevodnik, Živa Pohar-Marinšek, Janja Zalar, Hermina Rozina, Nika Kotnik, Tine Jerman, Jerneja Varl, Urška Ivanuš, 2020, original scientific article Abstract: ackground p16/Ki-67 dual immunocytochemical staining (DS) is considered easy to interpret if evaluators are properly trained, however, there is no consensus on what constitutes proper training. In the present study we evaluated a protocol for teaching DS evaluation on students inexperienced in cervical cytology. Methods Initial training on 40 DS conventional smears was provided by a senior cytotechnologist experienced in such evaluation. Afterwards, two students evaluated 118 cases. Additional training consisted mainly of discussing discrepant cases from the first evaluation and was followed by evaluation of new 383 cases. Agreement and accuracy of students' results were compared among the participants and to the results of the reference after both evaluations. We also noted time needed for evaluation of one slide as well as intra-observer variability of the teacher's results. Results At the end of the study, agreement between students and reference was higher compared to those after initial training (overall percent agreement [OPA] 81.4% for each student, kappa 0.512 and 0.527 vs. OPA 78.3% and 87.2%, kappa 0.556 and 0.713, respectively). However, accuracy results differed between the two students. After initial training sensitivity was 4.3% points and 2.9% points higher, respectively compared to the reference, while specificity was 30.6% points and 24.4% points lower, respectively, compared to the reference. At the end of the study, the sensitivity reached by one student was the same as that of the reference, while it was 2.6% points lower for the other student. There was a statistically significant difference in specificity between one student and the reference and also between students (16.7 and 15.1% points). Towards the end of the study, one student needed 5.2 min for evaluating one slide while the other needed 8.2 min. The intra-observer variability of the senior cytotechnologist was in the range of "very good" in both arms of the study. Conclusions In teaching DS evaluation, the students' progress has to be monitored using several criteria like agreement, accuracy and time needed for evaluating one slide. The monitoring process has to continue for a while after students reach satisfactory results in order to assure a continuous good performance. Monitoring of teacher's performance is also advisable.
Keywords: cervical cytology, cervical cancer, immunocytochemistry, accuracy
Published in DiRROS: 11.07.2024; Views: 1086; Downloads: 724
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4. A comparison of models for forecasting the residential natural gas demand of an urban areaRok Hribar, Primož Potočnik, Jurij Šilc, Gregor Papa, 2019, original scientific article Abstract: Forecasting the residential natural gas demand for large groups of buildings is extremely important for efficient logistics in the energy sector. In this paper different forecast models for residential natural gas demand of an urban area were implemented and compared. The models forecast gas demand with hourly resolution up to 60 h into the future. The model forecasts are based on past temperatures, forecasted temperatures and time variables, which include markers for holidays and other occasional events. The models were trained and tested on gas-consumption data gathered in the city of Ljubljana, Slovenia. Machine-learning models were considered, such as linear regression, kernel machine and artificial neural network. Additionally, empirical models were developed based on data analysis. Two most accurate models were found to be recurrent neural network and linear regression model. In realistic setting such trained models can be used in conjunction with a weather-forecasting service to generate forecasts for future gas demand.
Keywords: demand forecasting, buildings, energy modeling, forecast accuracy, machine learning
Published in DiRROS: 15.03.2019; Views: 3311; Downloads: 1537
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