Linköping Electronic Conference Proceedings
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Modeling and Control Design of an Educational Magnetic Levitation System
Get PDFA magnetic levitation system is a perfect educational example of a nonlinear unstable system. Only with suitable control, a small permanent magnet can be held floating stable below a coil. After modeling and simulation of the system, control of the system can be developed. At the end, the control algorithm can be coded on a microcontroller, connected to a pilot plant
A Penalty Function-based Modelica Library for Multi-body Contact Collision
Get PDFContact collisions are prevalent in mechanical multi-body systems and have always been a significant limiting factor for engineering technology development. This paper examines the fundamental types of contact in multi-body dynamics systems and explores their inherent topological relationships. Based on the multi-body dynamics theory and penalty function contact algorithm, this paper constructed the multi-body dynamics contact model using Modelica, which is a multi-domain unified modeling language. To enhance the applicability of the contact model library in the modeling of multi-body system, the contact model provides a connection interface compatible with the multi-body library in the Modelica standard library
DaLAJ-GED - a dataset for Grammatical Error Detection tasks on Swedish
Get PDFDaLAJ-GED is a dataset for linguistic acceptability judgments for Swedish, covering five head classes: lexical, morphological, syntactical, orthographical and punctuation. DaLAJGED is an extension of DaLAJ.v1 dataset (Volodina et al., 2021a,b). Both DaLAJ datasets are based on the SweLL-gold corpus (Volodina et al., 2019) and its correction annotation categories. DaLAJ-GED presented here contains 44,654 sentences, distributed (almost) equally between correct and incorrect ones and is primarily aimed at linguistic acceptability judgment task, but can also be used for other tasks related to grammatical error detection (GED) on a sentence level. DaLAJ-GED is included into the Swedish SuperLim 2.0 collection, an extension of SuperLim (Adesam et al., 2020), a benchmark for Natural Language Understanding (NLU) tasks for Swedish. This paper gives a concise overview of the dataset and presents a few benchmark results for the task of linguistic acceptability, i.e. binary classification of sentences as either correct or incorrect
Sustainability analysis and simulation of a Polymer Electrolyte Membrane (PEM) electrolyser for green hydrogen production
Get PDFIn recent years, green hydrogen has emerged as an important energy carrier for future sustainable development. Due to the possibility of not emitting CO2 during its generation and use, hydrogen is considered a perfect substitute for current fossil fuels. However, a major drawback of hydrogen production by water electrolysis, supplied by renewable electricity, is its limited economic competitiveness compared to conventional energy sources. Therefore, this work focuses on analyzing the sustainability of a green hydrogen production plant, not only considering its environmental parameters, as well as its economic, energy and efficiency parameters. The polymer electrolyte membrane (PEM) is selected as the most promising method of green hydrogen production in the medium and long term. Subsequently, a small-scale production plant is simulated using chemical process simulation software to obtain key data for computing a set of sustainability indicators. The selected indicators are based on the Gauging Reaction Effectiveness for the Environmental Sustainability of Chemistries with a Multi-Objective Process Evaluator (GREENSCOPE) methodology and are used to compare the sustainability of the simulated PEM plant with alkaline water electrolysis (AWE) plant. Finally, the process is scaled-up to analyze the feasibility of the simulated PEM system and validated against data to determine the operation of the electrolyser at a large production scale
A Comparison of Strain Gauge Measurements and FEA for a Confined Channel Geometry Subjected to a Hydrogen-Air Mixture Explosion
Get PDFUsing finite element analysis for rapid dynamic loads without validation of the results can lead to major miscalculation, thus making it necessary to examine the accuracy of the software. The structural response from a hydrogen-air mixture explosion in a confined channel is investigated with experiments and numerical methods. The channel measures 1000 mm in length, with an inside diameter of 65 mm, and 15 mm thick transparent polycarbonate sidewalls. Hydrogen and air were released into the channel and ignited. Four Kistler transducers record the internal pressures. A biaxial HBM rosette strain gauge was bonded to the polycarbonate sidewall, used for recording strains during the explosion experiments, where von Mises stresses were calculated from these recordings. The channel was then idealized as a computer-aided design model in the engineering software SOLIDWORKS. By utilizing the pressure data from the experiments and creating a three-pointed loading curve, finite element analysis was applied for obtaining numerical von Mises stress results. Comparing the experimental and numerical results of von Mises stress show a variation of 4.9%
Estimation of effluent nutrients in municipal MBBR process
Get PDFThe recently updated European Union’s Urban Waste Water Treatment Directive proposal, European Green Deal, Biodiversity Strategy for 2030, and EU’s Energy System Integration highlight a pressing need for innovative biological nutrient removal processes and energy-efficient control methods to reduce pollution and minimize the carbon footprint at water resource recovery facilities. The aim of the PACBAL research project is to develop estimation methods for nutrient profile in a novel industrial Moving Bed Biofilm Reactor (MBBR) process. This study devises and assesses a range of data-driven methods to estimate effluent phosphorus concentration by utilizing a combination of real sensors with software models. The resulting virtual sensor could facilitate the design of energy-efficient control strategies. The case study data are collected from the MBBR process at Hias water resource recovery facility in Norway. Data sets from December 2022 to March 2023 include varying weather conditions, such as rain, dry, and snow. The Hias Process consists of three anaerobic and seven aerobic zones, where biomass carriers removes over 90 percent of the phosphorus from the wastewater in simultaneous biological processes. The industrial online measurements include wastewater flowrate, aeration rates, dissolved oxygen and nutrients COD and NO2/ NO3 at inlet and total suspended solids at outlet. Dynamic data-driven models indluding transfer functions, state-space models and ARX models, were developed and compared to estimate the outlet phosphorus concentration. Model fitness to validation data was around 7% with ARX models, and up to 18% with tranfer function models and state-space models. The first and second order models gave similar results. The state-space models will be developed further and implemented to into virtual sensors that will enable energy-efficient control strategy development
Using live video for improving emergency response stakeholders` situational awareness and dynamic decision-making
No full textThe use of video for information collection and decision support for emergency stakeholders is highly relevant for future crisis management (Steen-Tveit et al., 2021). Not having the opportunity to see what is to be assessed in various crises scenarios is a significant obstacle to decision-making processes (Ek & Svedlund, 2015), and a lack of sufficient relevant information is a well-known limitation in crisis management (e.g., Van den Homberg et al., 2018).
The positive effects of using live video for information collection have been documented in studies related to collaboration between emergency management stakeholders (Bergstrand & Landgren, 2009) and interaction between the public and emergency management stakeholders (e.g., Bolle et al 2011). The information from videos can provide valuable information to increase emergency response stakeholders' situational awareness, provide an effective basis for decision-making, and aid the stakeholders to develop a common situational understanding. On the other hand, in the research on the use of video, it is often implicit that the video shows objective relevant facts for various situations. For example, body-worn cameras are considered "independent non-biased witnesses" of events (Lapowsky, 2014). But there are arguments that the understanding of video as "objective" is a misunderstanding, and that both how people interpret the video, and the format of the video itself, can be a basis for biased decisions (Granot, 2018). Also, some studies report that live video can introduce issues such as information overload and privacy breaches (Neustaedter et al., 2018).
Using live video for information collection in various settings in crisis management will become even more important in the future (Sæther, 2022), and there is still limited documentation of the impact video has on situational awareness, work processes, and decision-making. Research on this is therefore considered important and necessary. By observing the video systems during exercises, analyzing video recordings, and collecting data from experts through interviews and surveys, this postdoctoral project aims to investigate how the emergency response stakeholders in first responder agencies can utilize live video in the best way possible for improving situational awareness and dynamic decision-making.
 
ICT-Enabled Co-production for Better Emergency Response
No full textICT-enabled co-production is a research phenomenon that refers to a digitally enabled form of collaboration between formal public-service producers and external partners (usually citizens). The concept demonstrates unprecedented benefits to formal authorities in terms of finding optimized solutions to public services provision that are cost-efficient, legitimate, and effective. Yet, co-production started to earn prevalence in academia in the last two decades due to the developments in information and communication technologies (ICT), specifically WEB 2.0 applications. In the realm of emergency response, ICT-enabled co-production with volunteers is proving a critical necessity by increasing the readiness of formal responders and thus saving lives and resources. All that is in light of strained resources and increased emergencies, whether natural or man-made. For that purpose, we conducted a literature review study to understand how the phenomenon is addressed in academia. However, because the phenomenon is inadequately discovered, we adopted a grounded-theory-oriented approach to establishing data gathering and analysis. Hence, we soon concluded that this digitally enabled collaboration with citizens takes two different shapes: 1- digital volunteerism in large-scale crises (more extensive among studies and focuses on spontaneous volunteerism), and 2- ICT-enabled co-production in frequent emergency response, e.g., house fries, car accidents (less discoursed and takes more organized and coordinated fashion). Therefore, we expanded the scope over these two shapes to explore their opportunities and challenges. As a result, we came across similarities and differences in terms of enablers and barriers, such as the degree of “needed” official intervention, legal framing, technological support, etc. Most importantly, we discovered that ICT-enabled co-production (even though officially supported) still lacks a more apparent legal definition and more sophisticated technologies. On the other hand, we explored that digital volunteerism (even though bottom-up established by volunteers) becomes more recognized and takes different extents of organization with regular responders. Finally, inspired by the results, we draw out the lines for future tracks to conceptualize the phenomenon in order to 1- explore its importance and limitations in micro settings (local incidents) and 2- to understand how digitalized co-production can be utilized under more hazardous circumstances, such as wartime and civil defense
Employing gas sensor technologies for investigation of complex odor profiles
No full textIn the case of a mass disaster, terror attack, murder, war, or other catastrophic events, it is of outmost importance to find and rescue survivors, and to identify victims and human remains. Cadaver-detection dogs (CDDs) are trained and employed in forensics investigations due to their extraordinary olfactory capability. They are considered the most rapid and efficient tool for odor detection. However, there are critical legal and ethical concerns about using CDD results as evidence in court. It is, therefore, necessary to find innovative solutions that may help investigators to overcome the existing constraints.
Here, we present our preliminary results on the use of gas sensor technologies and quantitative methods for identification and classification of organic compounds that are key in odor detection. Due to the existing restrictions in acquiring human remains training aids, we used animal remains as training aids for laboratory tests under controlled environmental conditions. By use of linear discriminant analysis as a statistical method to analyze and evaluate raw data, we were able to clearly distinguish different samples of fresh meat as well as rotten meat (reindeer, deer, and chicken).
With our study, we aim to contribute to a better understanding of the highly variable and complex odor profile of training aids for further enhancement and, eventually, standardization of the current CDD training practices used to find missing people
Development of Pneumatic Technology for Automation and Control of Small Hydropower Plants
Get PDFSmall hydropower plants have been seen as a more sustainable source of energy in comparison with large hydropower plants due to the smaller required flooding area. However, every source of energy production has, inevitably, an impact on the environment. Aiming to reduce the usage of fossil-based products, such as hydraulic oil, a joint effort has been made between the Laboratory of Hydraulic and Pneumatic systems and the companies Reivax Automation and Control and China Three Gorges, in order to introduce the pneumatic technology to the hydrogeneration sector. Characteristics such as easy installation and maintenance, low acquisition costs, and mainly, low environmental impact, make the pneumatic technology an excellent candidate to replace the hydraulic servo actuators that have been traditionally used for automation and control in hydropower plants, which use large quantities of hydraulic oil and provide a high risk of a river bed contamination due to possible leakages or incorrect disposal of hydraulic oil. This paper presents two cycles of development of a pneumatic solution to automate and control the generating unit of small hydropower plants. It includes the first proposed solutions, proof of concepts and drawbacks that were faced, as well as the new challenges and achievements that rose during the design process. The paper also presents the most up-to-date results from a pilot project where a fully pneumatic solution was applied for a generating unit with 438 kVA of generating capacity and a model of development that was identified based on common activities performed during the first two cycles of development